Just like in real golf, the good and the great players will play a hole poorly, miss a short putt etc., but they are able to forget about it and move on to the next, que sera sera, they know they can't alter the past, whilst the average player, myself included, will let it play on our minds, hence affecting the next hole or rest of the round.
As far as vem/variant goes, i don't think of it at all, for me it works both ways, sometimes i think i have hit a perfect approach and it ends up miles away, another i have missed the ding badly and it ends up close, or even in the hole.