I often have "dry" spells, too, but I don't let it bother me. I know that there will be days that I can't or don't feel like riding, so I just accept that fact. I know I'll never be an uber-commuter like some folks here, but then again, I am not trying to be. Besides, when I do get back on the bike after a break, I feel a little stronger and I remember why I like to ride in the first place.