They are several artists named "Best Friends"

1) Best Friends are Lewis Sharman, Tom Roper, Ed Crisp and Jack Collister from Sheffield, UK.
They self-released their first 7 track "EP" in 2011 before signing with Art Is Hard Records in 2012.

The first release for the label was the "Throwing Up EP" which featured the songs "Wasting time" and "Break my neck". It was followed shortly after by the split with Grazes, that included "Dude Love" and "Mankind". In 2013 the band released a double A-side with "Happy Anniversary" and "Nosebleeds".

http://bestfriendspartyhard.bandcamp.com/

2) Best Friends was a screamo band from the US.

3) Best Friends is a screamo band from Australia. Didn't realise the name was already taken in the genre. Sorry US BFs