So I've heard my son is "difficult" on two different occasions from other parents in his class. It is very irritating, but I have only laughed it off and replied that he is an interesting boy that loves to talk and think (or something like that).
He is certainly a challenge at times, I don't doubt that for a second, but it is so irritating to hear it from other parents. I find myself thinking things to the effect of, "at least he's not a brain dead follower like your kid", but I know that's awful and probably not true, so I would never say that (unless maybe the same parents make another negative comment about my kid).
Anyways, that's the first issue/topic. Anyone have similar experiences? What's the most effective comeback line?

Second issue/topic. So, my son is difficult. He's 7 years old, in second grade. This is normal I'm sure. He is very negative at times though. When we ask him if he had a good day, he always focuses on the negative, even if it's just one small problem from early in the day. He gets angry quickly and often yells about things. He can also be extremely considerate and thoughtful. He just has a huge range of emotion. I'm sure it's best to be very even with him, try to keep my own emotions consistent and mild, but sometimes I react to his outbursts.
Yesterday I watched him from a distance at chess club, and I saw him react to some kids that were lightly teasing him about his Frodo Baggins costume (there was a literary character costume contest). A boy asked him what the name tag said, and my son told him but the boy then called him fruit loop baggins. My son immediately got mad and when another kid laughed and repeated the name, my boy yelled, "just SHUT YOUR MOUTH!" This stopped the conversation, but I was a little upset at his behavior.
He hasn't always been this volatile. Is this normal? Any similar experiences? Is it an indicator of frustration academically? socially? (I personally think it's hard for him to make friends - he gets bossy - can't figure out how to change this. I was never this way growing up.)