1. it's generally not an insult to call someone old. whoever you are saying it to, generally knows what age they are and knows they are older than you. when you try to insult someone by calling them old, you look immature. Think about whether you'd feel insulted if you got into an arguement with a 15 year old and they called you old.
you'd laugh and think they were an idiot for thinking that was an insult.
2. on the same hand, its not really an insult to tell someone they are young and have growing up to do. they will just think you sound old, and not really consider it an insult. nobody EVER thinks they have a lot of growing up and learning to do... they think that whatever their age is- that they already know about life.
3. insulting someone by calling them some arbitrary name does nothing. if i tell AAP he's fat and ugly, do you think that will bother him? he's NOT fat and ugly. telling someone that owns a house or has a good job that they need to go back to their trailer park or factory makes you look stupid and naive, and not very original.
4. Leave people's kids/parents/spouse out of any insult. it makes you look lower than low.
5. the "BRILLIANT!" thing is overplayed, but it is a good way just to end it and get in the last word.
6. the best insults are anything to do with calling someone canadian.