It really ruffles my feather when I see people taking the elevator when they could just take the stairs.
Why does it bother you so much to see people using an elevator?
I don't like people who care little about their well being.
While you're right that it's important for people to look after their health and well being, not everyone always has the stamina or time to take the stairs. It's also possible that they exercise regularly in their spare time so they don't need the workout from taking the stairs. It's best not to judge people based on minor things.
I don't care, I just wanted to express my hate is all.
Wouldn't you rather find things to be happy about than to walk around angry about minor things? Focusing on the positive things in your life will help you feel better! Looking at the bright parts of your day and focusing more on yourself rather than worrying so much about what others do will make you feel more fulfilled.