Without belaboring the Serena Williams situation TOO much, because I believe she is starting on the right path to having this judged as "one of those things that sometimes happens", I'd like to put a few situations I ran into as a softball umpire out there for consideration.
There are four or five particularly relevant moments that come to mind, and up front, arc or slow-pitch softball is MILES away from hard-core NBA, NFL or even tennis tournament umpiring. When you do leagues, you *almost* become friends with the players; the greatest compliment I ever got was the player who said, "I hate the way you call the high strike, but you call it the same all the time." That's essentially what both umpires and refs of any station should be shooting for, because there is NO doubt that players will always want to question your basic fairness if you deviate slightly either direction for or against us or them. You see an NBA ref that seems to be explaining things with a coach while watching a free throw, well, sometimes you have to invest some explanation time vs. just saying, "I made the call."
The most profound and closest-to-the-Serena type moment involved 'Mongito' in Tampa, FL. After having been called out by the plate umpire on a ball barely above dirt level, he pounded his bat on the ground leaving the batters box and half-shouted, "Jesus!" in frustration. That ump, a *very* straight-laced and religious person, immediately ejected him from the game for swearing, a fact Mongito's teammates let him know about just as immediately, and all HELL broke loose. I seem to recall at least three players restraining their 5'0" captain, but then the ump declared the game OVER and I *knew* the shit had hit the fan.
For the sake of accuracy, Mongito's team was Hispanic, and I was thankful that my buddy Ivan was able to explain that yes, the furious Mongito could put up $50 to protest the team's forfeit, but I really couldn't say anything about what the other ump had done.
Example two is simple: one of the players used the N-word while complaining about his ejection by my fellow 'blue'. The runner came around third on a hit to center, the throw was great even if the catcher moved a little up the line, and when the runner plowed into him, the ejection was automatic--the rule is you *have* to slide. The fact that one team was all black mattered less than the all-white team having only nine players; the rule was you couldn't play with eight, so the ejection ended the game. The fact I was holding back a guy who was VERY thick in the chest and ready to go with the player over his use of that particular word is the opposite situation of the Serena case: the large, angry, black person happened to be the umpire. The point is, you see someone with that kind of fire in their eyes, you have every reason to be afraid.
Situation #3--Long fly ball, actually out of bounds (but no fence) is caught in left field, and runner at second tags and goes. The throw to third hits a light pole and *richocets* into center field. Not knowing the ground rules, I call time and go find the complex supervisor, who tells me its runners advance ONE BASE. Wearing topsiders and a tank top, I'd fill in for the game during a tournament with a pretty decent competitive reputation. Whether it was the informal attire vs. my usual 3-patch blue shirt, shorts and cleats that failed to engender respect, I don't know, but even after explaining the ground rules, that team, and one female in particular, kept after that call constantly for was seemed like forever. Finally I took a couple steps towards their dugout and said, "I hear ONE MORE WORD about it from *anyone* and SHE goes!" Amazing the power you feel being right, and they didn't test me.
The final situation, home team down by one in the sixth. Base umpire calls first batter out when he's safe, the second, an obvious make-up, safe when he's soooo out, which causes the entire infield to jump on him. He calls time, asks if he blew it that bad, to which I saw Oh yeah! His only out is to ask for my help by saying he was blocked on the call, something that should NEVER happen on a play at first. I call the runner out, they get a run anyway. Bottom of next inning, batter hits a towering fly to right field, where the outfielder is playing him like he is King Kong. While he runs in and takes the ball on a short hop and pegs it to second, the batter never gives up, slides into second with a bang-bang play. The other ump, who'd drifted towards the outfield on the fly ball, turns around AND SHRUGS HIS SHOULDERS! He didn't have a call on the play. I saw it, call the runner out, he goes as ballistic as Serena, uses the right (or wrong) combination of words and I toss him.
I don't know why the foot fault call couldn't have been reviewed. The technology was certainly available for any other service or line call, and while I personally feel Serena wasn't going to beat Clijster's that night in any case, if she could say, "You've got to be F--king KIDDING me! Put that crappy call on the Jumbotron!" like McEnroe would have, things *might* not have escalated to the point they did.
As an umpire we had a saying: "The only guy you can count on out there is the one dressed like you." While it was a brutal time to make a call like that lines judge did, the chair umpire HAD to back her, especially in light of the frightening spectacle Serena screaming like that provided. You might say, like I did about Mongito and his team being bounced, "Hoooooo-ly SHIT!" at which side you have to stick with. Truthfully, I've turned to other people at tennis tournaments and said, "What game is she watching?" and at the end of the whole affair, you can see why they put instant replay into football and yes, instituted the 'Mac-Cam' in tennis. Two looks at the instant replay could have spared everyone a lot of grief.
And for sure, umpiring softball is definitely easier, even when I did a medium-pitch league and called like 10 walks on this one pitcher who kept complaining about my strike zone, and then I found out he was freaking *blind* in one of HIS eyes...