Does it really matter?
In the NBA, teams often battle for a better seeding during the regular season, in the hopes that this will earn them the coveted home-court advantage in the best-of-seven playoff series. However, it may be counter-intuitive to imagine that seasoned professionals are affected by something as mundane as the location of the game. Why does this minor detail appear to have such a large effect?
Repetition: The simple act of repeatedly putting shots up on the same court can result in on-court familiarity, just like it does for amateur players all across the world. Even though most courts are rather similar, they do have their own small quirks and differences. For instance, the Denver Nuggets play in a stadium at elevated altitude, and this can lead to adjustment problems for their opponents.
Familiarity: Besides on-court familiarity, off-court familiarity matters too. Players tend to have settled into their home city, with their own comfortable house, their family members around and perhaps even the comfort of home cooking. All these aid in relaxation and establishing routines.
Rest: In the NBA, this is particularly important as the games are played all across the country. By removing the need to travel, players are more well-rested and do not have to combat the effects of jetlag. They may have more time to prepare for the games as well.
Atmosphere: Screaming rival fans and a generally hostile environment can play a part in shaking the focus and confidence of even professional players. This can disproportionately affect young players sometimes, although there are players who thrive off playing in a negative atmosphere too.
Officiating: Even though this may not be intentional, it may be human tendency for perception to be affected by atmosphere too. Experienced referees may be able to function at peak condition in any environment, but some studies in other domains have suggested that these effects are not entirely negligible.