The term "Don't Get Attached"

Seriously, it's a passive aggressive way to place blame on the person you're being friends with for simply liking you more than you like them and so you can use it as an excuse later on. If you want to be an eternal bachelor/bachelorette, fine be one, but say so. At least be honest with others and even more so, with yourself.

Don't place blame on someone for wanting more than you want. There are no winners in those kinds of situations anyway, just different degrees of losing.