All the Time.
It basically boils down to this: my relationship with myself is an all or nothing ordeal.
I expect perfection from myself in most every aspect of my life, and if I'm not perfect I feel like I'm worthless. Failure and rejection is not something I can take lightly, and so much effort is spent trying to understand what went wrong. I suppose this would be a good trait to have, if only I didn't obsess over these failures for so long.
This trait manifests itself in my actions a couple different ways. Firstly, such introspection leads to me be very hesitant of trying new things, because odds are I won't be good enough at them. And then if I do happen to will myself to take that first step, anything besides success is catastrophic for my self confidence.
Probably the best example of this is my love life. I take the rejection personal, that their disapproval must automatically mean there is something wrong with me.
For someone who likes to think himself intelligent, you would think I'd be able to shake off such a ridiculous notion.