Dude, you are describing like 80% of the population of men that go to the gym. Especially High School age, guys.
Welcome to every gym ever from now til the end of time.
Guys do biceps/chest, women stretch & do cardio.
Personally I think a lot of the gym going women are worse off than guys, who wants the hell wants an 80 pound anorexically skinny woman?
and I really don't understand. I am definitely not the most educated guy in exercise, health or bodybuilding matters but common sense tells me I can't work out just one part every single day because after a while that part will get burnt out.
After a while, you'll run out of things to do if you just care for one body part and you should be gravitating automatically towards other body parts just to use your gym time and avoid boredom... no need for extra knowledge or wisdom there and yet, people grab the bar and do pull-ups mindlessly.