Guys you can't live with them and you cannot live without them

Have you ever met a great guy, started hanging out with him, and just as you thought things were starting to go somewhere, he totally FREAKS OUT and disappears? Or how about this scenario: You're dating someone you really like. You're pretty sure he's going to ask you to be his girlfriend, when all of a sudden his EX girlfriend magically reappears and suddenly your guy gets "confused" and FREAKS...