Death, taxes and fans complaining about calls that don't go their way.
As long as sports have existed, there has been an element of error that comes with living, breathing human beings officiating those sports.
However, this MLB postseason feels different.
At a time when the on-field product should be a showcase of the best and brightest the sport has to offer, the focus of the 2021 playoffs has instead drifted to missed calls and the impact that human error could have on who is crowned World Series champion.
The checked-swing strike call on Wilmer Flores to end Game 5 of the heavyweight NLDS clash between the Los Angeles Dodgers and San Francisco Giants was arguably the first-round's defining moment.
Flores was 0-for-17 with eight strikeouts in his career against Max Scherzer. If that pitch were called a ball, there's a good chance the next one would have sent him packing anyway. Nevertheless, it was a tough way to end a series, and it provided an enduring visual representation of poor umpiring.
With that moment still fresh in the minds of baseball fans everywhere, home plate umpire Laz Diaz picked a less-than-ideal time to have an awful day at the office Tuesday night.
His blown strike-three call on a 1-2 curveball from Boston Red Sox right-hander Nathan Eovaldi to Jason Castro with two outs in the top of the ninth inning opened the floodgates for the Houston Astros in Game 4 of the ALCS.
Castro delivered a go-ahead RBI single later in that at-bat, and the Red Sox unraveled in what devolved into a seven-run inning en route to a 9-2 Astros victory.
While it was certainly the most memorable, that was far from the only ball-strike call that Diaz missed.