I notice this a lot in my own life too. I seem to be drawn towards my worst fears. Like when you go near a cliff edge and feel a strange compulsion to jump off. Whenever I think about the worst that could happen in situations, there's something inside me that almost wants it to come true. I don't fully understand why, but I'd love to find out what's really going on.
I guess part of it is just a natural curiosity of finding out where life's boundaries are. Like a child that does naughty things to see what will happen. I wanna know if I'll be ok if the worst really did happen, or whether it'd be too painful and I'd know to steer clear in the future.
Also I think sometimes the world tells you you're supposed to be a certain way, and sometimes our self-sabotage desires are more of a rebellion against what we perceive to be bad advise from society, or false messages. You know, is life really about good grades, a mortgages and wearing suits and ties etc.
Or maybe sometimes the pressure of trying to do the right things all the time can be too much, so we might desire to purposely do the wrong thing just to release that pressure, perhaps.
There's probably lots of reasons why we sabotage ourselves I'd imagine.