when, after flirting with another individual while under the influence of an outside substance (alcohol, music, atmosphere, etc), you encounter said individual and regret your previously flirtatious actions; this feeling can be especially strong when "hanging out" was suggesting, and said individual attempts to make a later encounter occur.
Mark: I just saw that girl from the party and she asked for my number so we could go to a movie.
Alex: You should have never talked to her, man.
Mark: I know. Total flirter's remorse