Sometimes you get an itch on the edge of your awareness, moving slowly toward your consciousness, where it will eventually get enough steam for you to be aware of it, to attract your notice to a wound you were previously oblivious to. A small cut on your finger, perhaps, or a scraped elbow you hadn't noticed when you bumped into something. The pain wasn't noticeable before, & it isn't noticeable now really, but you have an awareness you didn't have previously. You've been injured.
You were injured before, the entire time since you nicked yourself on a ragged bit of metal, or got that tiny slice from a piece of paper. You were always injured, you now realise, but now you know. That changes things. Even if you shrug it off & continue doing what you were doing before, that slight pain has an origin, it has a reason. Now it's real, not just a dim awareness you didn't pay attention to. You weren't aware you weren't paying attention to it at the time, but now, in retrospect, you can remember how it happened. Something small, that any other day wouldn't have broken the skin, but now you're bleeding just enough to call it "bleeding" but not enough to do anything about it.
So you push it out of your mind & keep doing whatever it is you need to do, only now with a slightly irritating discomfort. It starts to burn, rather than itch, & you're annoyed that such a small thing could be causing you so much annoyance.
Some time passes, & you again become aware that the pain has somehow worsened. It's still not a serious thing, but you look back to the injury, & it's slightly discoloured. It's a bit swollen - it hurts a bit when you poke it, which you do. You keep poking it, in fact, the oil & whatever else from your finger getting in it, no doubt. What if it gets infected? It won't, it's small.
But it does. It does get infected, & it starts to ooze a bit. It's become sort of disgusting, & you no longer want to touch it, & you're pretty sure if you did it would hurt. It needs some kind of treatment, but just looking at makes you anxious. It'll heal on its own, if you stop messing with it.
But it doesn't. It gets worse, & people start to notice. "Hey, are you alright?" Yes, I'm fine, it's just a scratch don't make a fuss. It comes out harsher than you meant it, but they should mind their own business anyway. You'll deal with it when you feel like it, when you feel up to it, & not before. "No, I really think you should-" Yeah well I think you should worry about your own shit! Asshole. You know you'll have to do something, though. You'll put a bandage on it.
You go home & put a bandage on it & it feels better, the pain isn't so noticeable now. It's fine. You go back to work, & people nod toward the bandage & you awkwardly apologise for being such a dick. They forgive you, everything's fine now. You feel sort of silly for being so obstinate about it in the first place. You're relieved to put it all behind you.
A few days later you're feeling woozy & sweaty. You develop a fever. Blearily, you get yourself to a doctor for some medication. She looks you over, nodding & clicking her tongue while you stir impatiently. She asks if you have any injuries, but you've forgotten all about the bandaged wound. You say no, & she frowns. After looking at you for slightly too long with an insufferably thoughtful expression, she asks about the bandage. That? That's nothing, it's fine. She wants to take a look. You push down a momentary, irrational urge to say no. She's a doctor! She can look at it, right? It's no big deal, it's probably healed by now.
But it hasn't. In fact, it's so bad now you don't even recognise it. She draws back, a sharp intake of breath, but it's drowned out by your own. You stare at it in horror. Why didn't it hurt? It hurts now, though, making up for lost time. You can feel it throbbing under the unnatural swelling & colour palette that only be described as "sickness". The doctor says something you can't hear. What? "You need to go to a hospital," she says again. Your heart is thudding in your chest now. Hospital? It's just a scratch! It's a bit out of hand, sure, but can't she just give you something? No, she's very insistent. But you had things to do that evening, you were really looking forward to ordering some food & watching a few episodes of...whatever it was you'd wanted to watch. Not go to a hospital. You hate hospitals, they're full of sick people.
You thank her, & get up to leave, but she blocks your path. Suddenly, the world is different. You're trapped, now. You know that the longer this goes on, the harder it will be to get out. You move to step around her, put she puts her arm out. The movement is gentle, but now to leave you'll have to escalate the situation. Now violence exists in a way it hadn't before. You lock eyes with her. You only have a second to decide. If you hesitate, your life is no longer your own. You're a patient. You're a problem that someone else is going to fix. Decide, now.
This is what "crashing" is like. Some small thing someone says to you, or a mistake you make, or an awkward interaction, a harsh word, some small thing not panning out the way you'd hoped. You don't even notice it among the hundred things that happened to you that day, but it does something it shouldn't have, & it sucks away your positivity, like a tiny hole at the bottom of a jug of water. A slow trickle at first, but the draw starts to affect the entire body, slowly transforming it into a whirlpool that drags everything downwards.
It's something so small you can't really explain it, like someone explaining they're in the ICU for a papercut. It just sounds stupid, & doesn't call attention to the actual problem. Worse, the person who handed you the piece of paper will inevitably try to blame themselves for your predicament - the plight of the patient is that their agency is removed. Something as innocuous as handing someone a piece of paper causes guilt, which isn't what you want. You wish you'd done something about it sooner, but you didn't even realise it was there, how could you have fixed it? By the time you recognised the harm, it was already too late to do anything about it.
Worse still are the people who insist that it "must have been something else." Something so harmful can't be from such a tiny injury. They, & everyone else, deal with that sort of thing all the time. So do you, you insist, just this time it- they don't really listen, though. They assume your incompetence so abnormal you must be oblivious to the more obvious cause. Or they do listen, & suddenly you're the guy who can't handle a papercut. This is why you didn't want to deal with it in the first place, & you know what, you were right not to, in a way.
So the next time you get some small wound, something not really worth noticing, you're even less inclined to deal with it. You just want to get back to normal, back to the way things were. You push it out of your mind & keep going, back to normal, back to normal. Next time it happens, you're more careful to hide the wound from people. Don't want a repeat of last time, gotta get back to normal!
If the cycle repeats itself enough times, it becomes banal as any other routine. You start to expect it, and you stop trying to "get back to normal." In fact, you're pretty sure there never was a "normal" for you to get back to. This is just life, now, a constant rise & fall of mood where every period of "normal" is inevitably punctured, that same whirlpool forms in your consciousness, draining away your joy. It's boring, now, the process unfolding with a tedious inevitability, becoming more & more refined until the turnaround is measured in months, then weeks, then days.
Eventually, you learn not to try to be "too happy," because the better you feel, the harder you're going to crash. Life stops being about achieving your dreams, following your high hopes, being all you can be, it becomes about managing your next crash. It becomes automatic, like any boring thing, you don't even need to think about it. Don't hope for things. Don't be happy about things. Don't fly too high. Everything you achieve or attain for yourself is dangerous. People wonder why you never seem happy, tell you to cheer up, & you smile & nod enough for them to leave you alone.
"Cheering up" is for other people.