According to the Biography "One of a kind", Stu Unger was a big winner in the cash games he played. Since that was written, edited and reviewed by his contemporaries and friends - including a lot of negative stuff, I find it far more credible than your assertion.

I am not and have not disputed that tilt has an emotional core, because it clearly does. I submit that the primary emotion is frustration born from things not going well. Lack of playable cards, overpairs beaten by sets, river suck-outs, etc. In short, a series of low-probability events.

Knowledge lets you know that it's just bad luck and softens the blow. As I said before:

Poker knowledge is like the Covid vaccine: it won't stop you from getting sick, but you won't die.

Well it's kind of that thing with Stu in cash games that if you are the 10th best player in the world but playing against the top 9 ... it's a problem. Brunson, Baldwin, Puggy, Reese, Treetop, Chan, Slim, etc. I saw him spewing every time I saw him play in cash games, but that was only during the Series. Maybe he feasted on tourists the rest of the year.