But if you look closely enough even the most self-attacking behaviours can be understood. And if we can understand it we can also change.
Take self harm, for example. It seems to be a clear, deliberate effort to cause ourselves pain. But quite the opposite is true: self harm is an attempt to manage intense emotional pain - a form of intense distraction to shock attention away from painful thoughts and emotions. The physical pain is the price of ridding one's self of the emotions.
The key, when we try to make sense of these things, is not whether they are a deliberate effort to hurt ourselves. It's asking, what is the short term payoff? Seen from this point of view, all these behaviours make perfect sense. They are either an attempt to cope with painful emotions or overwhelming tension, or a way to avoid them.
We bail out of the job interview because the performance anxiety is overwhelming and we fear failure: avoidance offers short term relief. We drink or use drugs to escape distress and tension, even though the long term costs - hangovers, health problems, addiction - all outweigh the short term relief.
It is human nature to favour short term relief. And no more so than for people who have experienced chronic childhood trauma, or are, for whatever reason, in the grip of overwhelming distress.
We all make seemingly "bad" decisions when the future ceases to exist.
There is an old maxim in therapy that we need to cherish and respect our defences - those things we do to get us through tough times - because they helped us survive. To see them as self destructive is to dismiss as wrong that which enabled our psychological, or even our physical, survival.
Of course, everything human beings do makes sense - if you know enough about the situation. So if you find yourself judging someone as self-destructive, it probably means you've failed to truly understand the pain they're in, or have been in in their past.
WHERE TO GET HELP:
If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call 111.
If you need to talk to someone, the following free helplines operate 24/7:
DEPRESSION HELPLINE: 0800 111 757
LIFELINE: 0800 543 354
NEED TO TALK? Call or text 1737
SAMARITANS: 0800 726 666
YOUTHLINE: 0800 376 633 or text 234
There are lots of places to get support. For others, click here.