When I used to twitch:
Sitting in a pub in Sheffield, with birding mates, discussing the Varied Thrush in Cornwall. Only one of us decided to go - and he connected next day. The rest of us still need it (& for me, for my world list!)
Like Temmie I really regret not trying for Gurney's Pitta when I had the chance.
I was lucky enough to see a Gurney's, which I saw several times, and I should be grateful but it was a female - still satrt but just not the same - so I still feel like I dipped.