It's definitely tilt out of boredom. And in my case, it worsens with mental fatigue when I play for many hours.
I think revenge in poker is a lot of nonsense, it doesn't make any sense to me. Obviously, losing is very frustrating, especially when you have a much better hand, but the other player is participating in the same tournament, with the same hand as you, subject to the same rules. Why would I have any sense of vengeance? It doesn't make sense.