When I actually stop and think about the game of baseball, a lot of the things that we take for granted are actually things that we should not only pay attention to, but things that amaze me. How perfect and smooth the game is is often ignored, but it's amazing how perfect baseball is.
What am I talking about? Take the 90' bases for example. Why are the bases 90' apart? Is it just an arbitrary number? Possibly, but think about the things that the 90' bases gives us.
1. The difference between a hit and an out.
Any ball that passes through the infielders is a hit regardless of how hard it is hit and how slow the runner is. Even the slowest runner would have no problem reaching first base on a hard hit ball into the outfield. Any ball that hit at an infielder results (almost always) in an out, regardless of how fast the runner is. Then, the beautiful grey area of balls hit in the holes give us the exciting infield hit plays.
Okay, if the bases were 100' apart, batter runners would still have no problem reaching first base on balls into the outfield.
However, if the bases were 80' apart, we would such a large number of infield hits, that the game of baseball would become a mockery. What was previously out by three steps is now a bang-bang play.
2. The stolen base
Most stolen base plays are bang-bang. Base coaches often time the pitchers' delivery to the plate to see if it is favorable for their runners to run. The difference between being a good decision to run and being a bad decision to run is so close that it's actually not visible to the human eye; instead, we need a stop watch to tell us.
The bases are spread out just far enough so that the slow runners won't even think about running. (But, they still need to be held on by a fielder.) However, they are just close enough that a fast runner needs to pick his spots and get a good jump in order to be successful. We all know that a 70% stolen base rate is not good and an 80% stolen base rate is well above average, but what most of us don't know is how successful a runner would need to be for the stolen base attempt to be worth the risk.
Sabermetricians mathematically figured that number to be nearly 75%, right in the middle of what we considered to be good and bad. If a baserunner is successful less than 75% of the time, he's hurting his team by running into too many outs. If a baserunner is successful more than 75% of the time, he's helping his team by picking up an extra base every so often.
What amazes me, however, is the way that the 75% number was reached. It had nothing to do with the actual stolen base percentages in the league, but had everything to do with the natural rate of occurences of hits and outs in the game of baseball. It just so happened that the bases were 90' apart, just at the right distance for the best runners to have to work real hard to gain the advantage for his team.
Less than 90' and anyone and everyone should run. More than 90' and no one should run.
3. The execution of the sacrifice bunt
When attempting a sacrifice bunt, so many things need to be executed properly by the offense. The runner needs to get a good secondary lead and the batter needs to lay down a good bunt. Picture the perfectly executed sacrifice bunt though: the defense would have no chance at the lead runner, but an easy chance to retire the batter runner. In a poor bunt attempt, the defense has a chance to retire the lead runner. The 90' distance between the bases is just far enough so that the offense has to execute everything, but the 90' distance is just close enough for the offense to be assured that the runner will advance if it executes properly.
4. The reason for the sacrifice bunt
The third point, execution of the bunt, would be completely moot if the sacrifice bunt were not necessary. Again, going back to the natural rates of occurences of hits and outs, the decision to attempt to the sacrifice bunt falls within the grey area. If the average batter reached base more than the average right now, there would be no reason to give up the out for the base. If the average batter reached base less than the average right now, the offense should have no problem with trading the base for the out.
Instead, the natural rate of the occurences of hits and outs is just so that the decision to call for a sacrifice bunt is a well thought-out move.
5. Bunting for a hit
Similar to the stolen base, the 90' distance between the bases is far enough away for even the thought of the bunt hit is out of the minds of the slowest ballplayers. However, 90 feet is just close enough for the fast runners and good bunters to have to pick their spots and execute perfectly to be able to reach base more often than the natural rate of the occurence of a hit, so that bunting is advantageous.