Forgot to do what I wasn't going to do

Forgot it was Earth Hour last night. So instead of not turning my lights off when I was supposed to and feeling cranky about it, I instead left the lights on when I was not supposed to and felt apathetic about it.

Is it possible to be retroactively guilty about not doing something you never would have done anyway, but forgot about before you didn't do it, do you suppose?

UPDATE! - Suggested replacement activities for Earth Hour for those who don't care about it, but who miss out on all the feelings of self-satisfied virtue/guilt you have when turning out the lights:

COLIN FIRTH HOUR - Hour spent ogling pictures of one's favourite film star on the net, while feeling naughty about it

GIRTH HOUR - Hour in which you stop dieting on whatever diet you're dieting on, and instead order in a gigantic bloody cake, and guts out on it.