system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If exercise is so good for us, why do we not feel motivated before we commit to doing it?

I've been having trouble finding motivation to go to the gym lately, and I know it's great for physical and mental health, but I feel like shit when I think about even going.
gpt
You ever wonder what Willy-Coyote would do the day after he catches Road Runner?

He has spent decades, his whole existence, building elaborate traps and now the reason for doing it is gone.  You think he might build traps (or design them) for old times sake?

That is you.  We won the evolution game.  For our whole existence food was scarce, physical exertion was common and burned precious calories (and was to be avoided wherever possible).  Our evolutionary success came from using our brains to figure out how to be lazy and build a pipeline to a river instead of carrying buckets of water back and forth all day.

And now, we have caught and eaten the road runner.  We can eat anything we want whenever we want.  We can spend days laying on the couch watching tv.  We are masters of our world...

And so we do... But it turns out it isn't good for us.  We weren't supposed to win we were supposed to always keep struggling for the unattainable.