Back when UA was flying a JFK-SEA A320 nonstop, we were in a ground stop for ~4 hours at JFK due to thunderstorms in the area. Being an aviation geek and sim junkie, I ended up on the flight deck talking with the F/O for a good hour as the Captain had left the plane to talk to operations. After about 10 minutes, he said "do you want to sit down?" and there I was in the left seat.
I recall asking about particular approaches he found difficult, what hydraulic systems powered what when they did a single engine taxi, flying techniques, and all sorts of other stuff that you could ask about without being considered suspicious before 9/11. Aside from my 2 flights with Capt. Molly Flanagan, it's probably my best memory from a UA flight. It didn't hurt that as a lowly 2P at the time, I was in 6A, had an empty middle, and the gentleman in 6C was a 1K or similar, because the first class F/A brought him a sundae...and then asked if I wanted one too.
Not bad, when you think about it: a 4 hour delay is one of the best flights I've ever had on UA, and it was all about customer service.