I don't flirt. Or at least I don't do it on purpose. Probably have done it on accident, haha. ^^;
Honestly I hardly notice people are flirting with me. There hare been times when people point it out and I'm like "really?" It has to be really obvious or I won't get it.
When's flirting creepy? Depends on the person's saying and the person getting flirted on is uncomfortable. I just get uncomfortable with it most of the time because it's rare for me to notice and I don't know how to react.