Obviously, the frustration and the pain.
Sweating so much that your fingertips prune as it just drips off your body onto the floor and you feel like your pores are fucking FAUCETS.
Feeling sluggish and the ass pain after an intense session on the exercycle.
Not being able to find a comfortable temperature of shower between where it makes all the water feel like sweat and where I'm shivering and extremely uncomfortable, plus the sloppy wet feeling after a post-workout shower.
Things I LIKE about working out:
Being able to watch trashy TV without feeling like I'm wasting time
Time to think by myself
Knowing I don't have to do it again for at least 24 hours.
Overall, I'd SO much rather be riding my goddamned bicycle.