How should I react to insults?

I am at a shop and on the high street on some crowded day and someone randomly insults me.

What if a family member, friend or someone at work insults me and it is done obviously with the intention of an insult.

How do I react?

i say you turn insults to reality, therefore are no longer insults. ie: someone calls you a cock-sucker, you should get right down on your knees and suck his cock. after he finishes, get up right and his face and say "yeah! what now bitch!"