Johnny Damon was one of THE faces of Boston's return to glory in the early 2000's. Damon was a key cog in the Boston offense that finally ended the Red Sox's championship drought in 2004. Damon played well during his entire tenure with the Red Sox with a .295/.362/.441 slash line in almost 600 games in Boston.
However, Boston fans have never forgiven him for leaving Boston in free agency and going to the Yankees. It is one thing to make such a heel turn, it is another to do so after saying "There's no way I can go play for the Yankees, but I know they're going to come after me hard." Many Red Sox fans thought there was no way Damon would ever leave and even if he did, he wouldn't go back on his word. Well, apparently $52 million was enough for him to forget all of that and put on pinstripes and Boston fans haven't forgiven him for it.
Finally, we come to yet another case where a guy got paid well and did not play well in Pablo Sandoval. Sandoval was at one point one of the more beloved players in the league thats to his, um, relatable physique and style of play. The Red Sox signed Sandoval to a five year, $95 million contract with the hope that he could continue to be the sort of consistently strong and well-rounded player he was with the Giants.
Well, that very much did not happen. Sandoval showed up to camp out of shape and proceeded to put up the worst season of his career. After that, he dealt with shoulder surgery in 2016 that cost him most of the season and Boston eventually DFAed him in 2017 after he struggled at the plate yet again upon his return. Again, if you ever want to guess why a team's fan base hates a former player, the best bet is to guess that the team paid him a lot and he didn't do a lot.