Boston Celtics star Jaylen Brown has come a long way, and his new $304 million extension is a great reminder of that.

In high school, a teacher told Brown that he'd be in jail one day. Instead, the 26-year-old just signed the richest contract in NBA history. Since the Internet never forgets, people were digging up Brown's old tweet that shows just how completely unaware his teacher was.

Brown has forgiven his former teacher despite her cruel comments, and it turns out she's just one of many people who've doubted him along the way. For example, after being drafted with the third overall pick in 2016, the UC Berkeley product was loudly booed. Some Celtics fans wanted New England native Kris Dunn and plenty of scouts didn't believe in Brown's shooting ability.

Ultimately, the Celtics made the right choice, as Brown is a two-time All-Star who arguably hasn't entered his prime yet.

Those jeers weren't the last time Brown would be disrespected, though, as the longest-tenured Celtic has been mentioned in various trade talks over the years. All those rumors annoyed Brown so much that he eventually voiced his displeasure on social media last summer.

Presently, it's now apparent the C's are committed to him for the time being. His new extension has no player option and he can't be traded for a year, so the front office is putting its full trust in Brown and fellow stars Jayson Tatum and Kristaps Porzingis.

Following a disappointing performance in Game 7 of the Eastern Conference Finals, Brown will get another chance to prove his doubters wrong next season. The pressure is on, though, because if the Celtics don't raise a banner within two to three years, the Boston core will likely have to be split up for good.