Why do guys act all lovey dovey one minute and then mean the next?

[Hope_for_love]

This happened to my best friend her boyfriend was being rude but then am hour later was telling her he loves her

[Phoenix98]

I don't know some guys are just that way he could have been irritated had a crappy day at work, going through something etc then got over it who knows. I contain my anger though it never shows I always treat everyone with respect regardless of how I myself feel.

[Anonymous]

probably got a erection a hour later