Just played a sit n go on blue square (hand history doesn't work) i'll describe it as best i can remember.
5 players in an unraised flop of:-

kd
I have

and as it's checked to me i decide to try to nick the pot with a pot sized bet of 200ish, all fold to one flat caller.
Turn

he checks so i bet 300ish, again he flat calls.
River

and he goes allin, i call with my flush and he shows 4 5 for a straight.
Then.............he goes psycho calling me all sorts of things and rants and raves about bad beats!!!
Did i do wrong?