I suppose everyone has a nemesis. Superman has Lex Luthor. James Bond had Goldfinger. (Come to think of it, Q had James Bond.) And of course Dr. Doofenschmerz has Perry the Platypus (see below).
I have a bevy of nemeses. Self-doubt may top the list, but it gets an assist from a few cardinal sins: pride, envy, sloth. And gluttony, if there are any Double Stuff Oreos around. (Damn you, Nabisco! Damn you!)
Self-doubt is a real writer's nemesis. I mean, think about it. You wake up in the morning and here comes another day of you and a blank screen and the hope that whatever you manage to put on it will actually be of some use to somebody. I guess if you write technical stuff or clothing catalogues for a living there is a reasonable chance that this is actually the case. But if you're writing a book you've been working of for two years or a spec screenplay, well then. The odds diminish a bit, don't they?
I mean, that's only being realistic.
Here's a debate question for writers:
Reality: Friend or Foe?
I'll have to pick that up some other time. In the mean time enjoy the clip. I just love "Phineas and Ferb."