Phobia of a weaker opponent
I believe, this interesting paradox is well known to everybody of low-mid rated players. Once you face an opponent that is significantly weaker, often you cannot win the game or even lose. I knew players that had a certain phobia of playing weaker players because that made them feel unease. Indeed, winning someone rated 300-400 points below gives you 2-3 point increase, whereas even a draw bites off about 7-8 points of your rating. If you are strong - prove it. There is no way for you but to win a weaker player.
Simple question is asked - Why do we lose to the weaker players?
I think, I have got the answer (at least for myself).
Firstly, playing someone weaker you get relaxed thinking that the win is easy. That is not the case. Your experience and skills might not even help if you are in a bad position or blundered. As someone said "There are no good moves in a bad position". Every win must be earned and proven OTB.
Secondly, weaker players tend to love tactics. That's how their study of chess begins - tactics, combos, attacking the king. You get relaxed and fall into unexpected tactics.
This paradox resembles the situation when a played cannot win (and sometimes even loses) in a winning position. Being convinced that the win is close and the game can be won "anyhow" played relaxes too much, whereas the opponent is trying every chance to survive.
Here is my latest example where I was fighting for survival (playing White). This was a rapid game, and many things depended on time. Yet I must say that Black's rapid rating was higher by 160 points, and he had almost twice the time I had in the below position.
That reminds me of Dostoevsky saying that prey is more cunning than predator as in the battle the stake is prey's life. The predator merely seeks food, and if not now that could wait for later.