When you don't want to, can't, or it wouldn't be prudent to claim to have only one best friend. You have plane friends. They are best friends that you would jump on a plane for if they said they needed you.
Choose your plane friends carefully because they would also have to be willing to do the same for you. Generally, you don't have these until you are an adult and all your friends are scattered throughout the country.
I don't see Marc that much, but his still one of my plane friends.
Bowling where you order a bunch of mystery shots that the bartender gets to choose. Then when a person gets a strike they get to give one of the mystery shots to someone else that is bowling. Neither the person giving or taking the shot knows what it is. This continues until all the shots are finished or someone starts throwing their ball in the wrong lane.
Cadillac Rules: If no one gets a strike in the first five frames, you get to give shots away if you get a spare.
One and Done Rule: If you choose to keep one of the shots for yourself instead of giving it away.