system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do humans tend to have bad postures when we should be instinctively predisposed to keeping our backs straight?

I've had bad posture all my life, and when I notice I'm standing badly I try to change it. But it's just all the time, I get focused on something or stop paying attention and my posture returns to being kind of slouchy.

Shouldn't we naturally always stand up straight?
gpt
Homo Sapiens evolved in an environment in which they rarely sat and ran for hours every day to survive.. Today's humans are standing less running less squatting less and sitting a lot more than they've ever been able to.