We used to have a "resident heckler" in our local folk club (sadly no longer with us): he always sat in the front row, so as a performer, you COULD usually hear what he was saying, and hopefully come up with some brilliant repartee.he was, on the whole, very funny.
Some 15 years ago, I wrote a song about being married for 30 years, and challenged the audience to say "what 30 years of marriage meant" hoping for the answer "Pearl Anniversary" - quick as flash comes back from yon resident heckler - "AGONY!!!!"