what does Phil Thomas play as black

[Andrew McHarg]

If Qxd4 with the correct follow up wins and you can't see the follow up and you consequently lose.... then Qxd4 is a blunder.

On that theme and it might not be the case in this game sometimes it is wrong to play the strongest move - sometimes the second strongest move is easier to calculate through to a win.

I think that's debatable. I'd be more inclined to suggest that missing the follow up is the blunder. Perhaps a mistake if you don't see the follow up prior to making it, but a blunder (to me) implies a move that immediately turns the whole tide of a game on its own.

But I agree that it's sometimes better to make the more obvious move that leads to an easier win, even if it's technically not the strongest. I've done that loads of times. Ironically, it often leads to a quicker win because the opponent resigns earlier realising there are no realistic opportunities for you to mess it up anymore.