I'd disagree that giving up on that workout was a good idea. I'm heavily involved in the powerlifting community, and there's a well-known phenomenon where people try and talk themselves into taking an extra rest day or two before "leg day" because leg day is so important that they absolutely have to feel 100% when they do it...problem is they do this every week, so instead of doing 100 leg workouts a year at 95%, they end up doing 70 leg workouts at 100%. And trust me, that's not a good trade-off.

The thing to realize is your mind is just trying to trick you into getting out of something, because leg day is hard.