what is the advantage of playing in ones home country !?

I hear this alot when masters talk about world championship matches in books,media etc... and when looking at past results there is most definetly a link that supports this claim but what exactly is it ? To me I always thought it just meant that the player (be it the world champion or challenger) who's playing in there home town is just more motivated to inspire fans but is there something more? One local expert thinks that more of that nations masters will be willing to assist there champion so the home advantage really is just more assistance but what do you guys think ?

Time zone. living in an area you are familiar with. speaking the language. there are tons of small advantages.

Ok that makes since

opponent has diarrhea from drinking the water

jejeje