It's not just other people you shouldn't trust. You should never trust yourself.
I don't mean to imply that you are or will be dishonest or degrading, degenerate or doltish, only that you'll never really know. Some well-meaning upbeats would say: "If you'll never really know, why worry about it?" If you never worry about it, I say to them, you are doomed to be an upbeat and therefore barred from the more exclusive parties and welcome only at mountain-biking expeditions.
It's not just other people who hide things from you; it's also you who hide things from you. The problem is, even if you figure out what you're hiding from yourself, you might never know why.
Take this entirely fictional scenario, for example: you hate your job. You find it unbearable. You hate everyone there. You hate yourself because of it and understand why everyone else there might hate you. But why?
Maybe you've always been a little bit lazy. You never liked your summer jobs. In fact, you've never liked work of any kind. You've always preferred watching hour-long crime dramas and "journaling."
Also, maybe you're inclined to exaggerate. Maybe your job isn't all that awful. Maybe you just dramatize situations to get attention or to prove that just because you have a totally sucky job doesn't mean you're incapable of telling a decent story. So maybe it's not totally sucky at all, in which case you have nothing to compensate for except for your own lack of self-discipline...
Maybe this job actually presents you with an exciting and honourable challenge and you're terrified of failing. In which case this job represents the pinnacle of all you could achieve and you'll never get anything better or more satisfying. So you have to work out whether you're in fact afraid of succeeding at the Best Thing That's Ever Happened to You.
Or, finally, there's the possibility that your job sucks. That everyone there sucks. And that everyone there really does hate you. You're not rationalizing anything away. In fact, worrying that you're actually happy there and can't accept it is actually a means of keeping you there even though you hate it. Because you're afraid you'll hate you next job even more? Absolutely. And you're probably right. Or are you?