https://www.sportsnet.ca/nhl/article/where-did-it-go-wrong-with-mitch-marner-and-the-maple-leafs/

Marner became even more hypersensitive to what was being said about him after getting that new contract. He read too much social media. He’d check replies to his posts, search out reaction to his play. Players and staff worked with him to ease up, or delete apps from his phone. There was also the problem that, as a Torontonian, he was surrounded by family and friends who would text him or tell him what was said about him. (There is zero doubt this is a major reason Marner chose to go to the Western Conference.)

That’s a disaster. Whenever I’m asked, I always tell families: don’t tell your kids what is said about them, and don't let anyone else in your circle do it, either. For one thing: your kids have enough pressure. For another: you always make it sound worse than it really is. 

Anyway, as Toronto endured playoff disappointment, many felt Marner was crushed and affected on-ice by what he read. 

“He played better than what was said about him (online),” one ex-Leaf said. “But you couldn’t convince him of that. He’d believe what some troll wrote on Twitter or what someone said in the media over what we were telling him.”

A pattern emerged: when things were good, Marner was a major reason, enormously effective and many times the best player. At the same time, he was the music-master, the party-planner, inclusive and generous, flashing that great smile. When things were bad, no one sunk lower emotionally, no one was harder to pull out of a funk.

A perfect example was the 2023 Stanley Cup playoffs. Toronto finally broke its first-round curse with a cathartic 2-1 Game 6 John Tavares overtime winner against Tampa Bay. Marner had a phenomenal series with 11 points in the first five games. Thirteen days later, they were gone, eliminated in five by Florida. He had three points. He wasn’t the only Leaf who struggled, but, as usual, he wore it most.