Warmed up to an episode of Modern Family on Hulu, then did most of the Spinervals Hills workout. Felt great until the last rep, when i really faded. Had eaten a big bowl of rice, beans, tuna, salsa, and cheese about an hour before, so was pretty well-fueled (unlike yesterday, when i had a major bonk and ended up eating a chocolate bar mid-ride). Skipped the last set, which i hate anyway (heavy gears, short sprints). I guess my policy is that I'll do it if I felt good during the rest of the workout, and will skip it if I feel bad, or if I think it'll kill my knees (which it often does). Oh well. Progress, at least.