I’ve only had one diversion, on a CX HKG-LHR in 1994. I was connecting, hence nobody had informed me they had to make a refuelling stop at FCO. The reason was that due to increased Taliban activity, Afghan airspace was off limits, CX had exhausted their overflight rights over Iran and Iraq, well it was Iraq. Therefore they had to fly around the whole thing. Took us about 14 hours to Rome, and when we landed they slowly taxied around as no ground crews were available until 6 am. A quick crew change & new catering loaded. My very long 6 hour layover at Heathrow became two.
Not a diversion as such, but a colleague of my dad was flying from Lisbon to Maputo but somehow ended up in Boston. This was back in the eighties so slightly different protocols. The challenge was that back in those days there were a grand total of four weekly direct flights from Europe plus a biweekly one on Interflug. I can’t remember how he finally got to his original destination, but we are talking several days.