I'm certainly feeling the latter. Yesterday, we ran the deck of death for the first time in over a month. According to my Fitbit, my pulse hit 180 (probably when doing toes to bar on the rings). By my final round of running, I felt like my ankles had weights attached to them; I had to force myself to pick up my feet and stretch out my stride rather than barely shuffle forward.
Thus, this morning I was quite tempted to not exercise due to the "too sore" complaint. This is despite knowing that the soreness often gets worse when I spend a day inactive. I'll probably be less sore tomorrow than I would have been if I hadn't exercised today.
Now, I need learn how to shore up my willpower and keep myself from eating away any of the extra calories that I burn from my exercise.