Make him feel better/troll him for being a simple aging mortal, sort of thing.
I totally agree he overstayed his welcome in DS9 and Voyager, but I REALLY liked the sparring and back and forth Picard and Q had, as well as some of the other crew. Favorite Q episode is Q Who, because it introduced the Borg and pushed Picard to admit he's only so capable...and yet still justifed humans going out there anyway. And then there's Deja Q.
"What must I do to convince you people?!"
"Die."
"Oh very clever Mr. Worf. Eat any good books lately?"
It's the writing that made it, and deLancie and Stewart's delivery that killed it, for me. The chemistry between those two actors was fantastic from day one, I thought.
On that note, if you ever get the chance, for the love of Rodden's berries please find Spock Vs Q. There's two of them, they're hilarious, and Nimoy and deLancie get along even better than Stewart. It's a joy to listen to if you can, and it's always nice to hear Leonard's voice again even if we'll never get a 3rd one.