It's probably the single worst thing that happens in the summer, besides falling asleep on the beach and getting third degree burns.
Your friend gets to go on vacation while you get to stay home, working, taking classes, or just participating in the nothingness that make up most summer days. So while your friend is off drinking at the swim up bar in paradise, here are some things you can do.
1. Hate them
Spend the entire week that they are away mad at them. Bring your other friends in on it as well. Any time their name gets brought up make sure you call them an asshole. How dare they go swim with dolphins when you are stuck vacuuming the pool at the beach club you work at.
2. Think up ways their vacation can go wrong
So your friend is chilling on an island. Cool. Enjoy the sea turtles, hope they don't bite your finger off because then we would have to call you stumpy for the rest of your life. Sun poisoning would be just god awful, but if she keeps drinking all those delicious fruity drinks on the sand its only a matter of time before they fall asleep and burn like a hamburger left on the grill.
3. Stalk their social medias
You know they are going to snap chat pretty much every second they can. Rewatch them so you can point out to your friends, coworkers, family, pretty much anyone who will listen, the tiki bar, the lobster dinners, the all-inclusive pool side bar (bitch). Resume #1 with the people you are showing.
4. Be actually excited for them to come home
Even though you spent the whole week hating their guts and hoping a seagull, pelican or whatever birds they have in the tropics (I wouldn't know I've never been), pooped in their strawberry daiquiri, you did I guess, miss them a little bit.
But only a little. So make them tell you all of the details about the trip and laugh at all the drunk stories they will have. Start planning your own friend trip for the following year which may or may not happen.
But the best part about them being home, they aren't in paradise without you anymore.