in my case it was the conrad bangkok mistake.

the 'highest gain' is subjective in this case...my gain was not so much because i got to stay in the presidential suite at the conrad in bangkok--which was fabulous, mind you--but because getting in on that deal was the moment that mr kk decided that my little hobby was NOT weird after all, and was in fact a very good thing for me to be doing. once he was on board, all the miles and points stuff got easier...and i've been 1k ever since, with mr kk supported mileage runs. that's entirely due to his getting to stay at the conrad...which goes back to that thread. ^