Far too many to mention - if I didn't have a love of flying I wouldn't be on pprune in the first place.
To narrow them down:
1) Saudia, 1991 - after a week delay getting a Saudi visa and then a 24 hour tech delay, we asked for the usual 5 minutes in the cockpit (3 of us bothers, youngest was 8 at time). We stayed there for the whole journey down the Nile, and my other two brothers got to sit in the jump seat to land at JED! I had to "make do" with a first class seat behind (we were all cattle SLF).
2) Anything on a twotter with Winair for obvious rollercoaster reasons!
3) Very reasonable food with Royal Brunei, and even on my most recent lh flight with AF. In fact, no complaints at all about Air France. Well - we weren't offered chicken or fish (and of us) - just chicken!
And I'd also add any other airline flying scenic approaches or take offs - although that isn't really a customer service issue, it is part of the flight experience.
Can't think I've ever had reason to lodge a major complaint - as opposed to simply accepting the cattle treatment (AA pretty bad for that).
I once strayed into the premium section on an AA flight - I think I was just looking for the nearest toilet, not a larger seat! After I'd sat down for a little while, a member of cabin crew came over and gave me a massive bollocking for straying into the "business" zone. Totally pointless, rude and aggressive - but I wouldn't have expected much better on AA to be honest.