The Steroid Era
This was one of the most polarizing long-term dramas ever because everybody knew what was happening. Barry Bonds, Mark McGwire, and Sammy Sosa all went head-to-head as they tried to break home run records. Yes, they achieved this but they, along with many other players of the era, had more juice inside them than a Snapple factory. It was entertaining but it was also very wrong.
In the end, MLB clamped down on rampant PED abuse but it continued to be an issue. Later, the BALCO scandal implicated dozens of athletes including Alex Rodriguez. Baseball gained a reputation for being a dirty sport because of decades of cheating. It’s fair to say that it has never fully recovered (via The Ringer).