What is it, exactly?
When I asked myself this question recently, it seemed to me that it was causing oneself pain or difficulty on purpose, ostensibly to achieve something desired.
Exercising at the gym
Watching the news on TV
However...the dictionary has several definitions, and three out of the four have one thing in common: *pleasure* is derived from pain, degradation, etc.
So, unless you're one of those crazy people who experience an endorphin high after exercising, that doesn't qualify, and honestly none of the other (admittedly humor-based) examples do either.
So though we joke that the friend who stays in the job with the craptastic boss is actually a masochist, that's not the description at all.
So what is? What makes us do things that are painful, tiring, saddening, frustrating, in order to reach a goal or obtain something that we think/hope will make our lives better?
(**Note: I am not a masochist myself, but there are times if I wonder if I am. ;)