system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it that Home advantage in most sports is a seriously considered factor. Example soccer where teams are notorious for not loosing at home regardless of opposition.
gpt
There are few factors that give a team home field advantage:

1) No travelling - When you play at home, you do not require to travel a large distance to get to the game.  You get to stay at home with your family and friends.  This generally allows the players to be more rested.

2) Field dimensions - In soccer, the size of the pitch does not require to be an exact size, but just with certain parameters.  So, some fields are skinnier while some are longer.  This can give you a large advantage.  Depending the team's strategy, you can adjust your field dimension to give you the advantage.  Teams with fast wingers for example might prefer a longer, thinner field.

3) Climate - Sometimes, teams withing a league play in very different climates, especially for American football.  Teams the practice in the heat will play better in the heat.  So if a team that is used to colder weather comes to play in hot weather, then they have the disadvantage.

4) The fans - The fans do play a part in the game.  Some plays in the game work better for the players if there is silence.  So naturally, when the away team comes to a critical play where they need a bit of silence to communicate and concentrate, the fans make as much noise as possible.  Also, in soccer for example, the fans sing a lot of chants.  These chants may sometimes distract the opponents and they can inspire the home team.

EDIT: Another factor is the influence of refs.  Refs are human and sometimes their decisions are based on the reactions of others, especially the fans.  They may be more willing to make a call if they hear 50000 people shouting at them to do so.