What's worst than people cracking and smacking their gum? ... GUYS who do it. Honestly guys, that is one of the most unattractive things you can do. On the street this morning, the guy in front of me cracked and popped his gum and then turned around and looked at me. Ugh, not pretty folks.
Oh, and another thing you can do to get me running the other way: smacking your gum while at the gym.