system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is "home field advantage" so important in professional sports?

I guess it depends on the sport, but aren't playing fields standardized?  Is it just psychological?
gpt
Well, in baseball, the field isn't standardized, so there's an actual advantage there for some players (it's why some parks are hitters' parks and some are pitchers' parks).

For everything else, it's mostly a psychological advantage that comes from having your own crowd cheering you on.  But there are other factors:  if you're on your home field, you might be more well-rested, because you didn't have to travel.  You're probably more used to the weather, especially in areas like Denver (thin air) or Florida (humid) or Minnesota (cold).  They're small advantages, but possibly important ones.