Default Bestie

When your bestie is only really your bestie due to lack of other friends. So they're only your bestie by default. They tend to drive you nuts and make you often question why you're even friends with them. Is often an old school friend or childhood friend and you're only really still friends with them due to knowing them so long as well as not having many friends. They tend not be a great friend or even a good friend really. Chances are if you met a better friend you'd drop your default bestie like a sack of shit.

Tom"UghI fucking hate Matt! He drives me mad!"

Mum" isn't he your best friend?"

Tom"Honestly he's a default bestie. Only reason I'm still friends with him is because I've got no one else"