"Wisely and slow. They stumble that run fast." -- William Shakespeare, Romeo and Juliet.
Many players when pitted against a stronger opponent try and swap everything off and get a draw in the endgame. They then get a worse game, and are ground steadily down by their opponent's superior technique who is pleased to get a win without danger of losing. Every exchange made is going to be better for one side or the other, and every passive move makes your position less promising.