These were the pre-FOMO days.
People have always been jealous of one another, Lucy and Ricky's fictional friends included, but these days the diversions of our friends are much more in-your-face than they were in the past. In the digital world of instant sharing, everyone can be immediately aware of what you're up to and then can be immediately jealous that they weren't a part of it.
Most people stick to sharing positive moments on Facebook, so you end up hearing a lot about the good times. That encourages you to compare your life to there's, and whether you're doing your own exciting things or not, some of us fall into "the grass is always greener" trap.
So what do you do when a friend posts that they just had the best day ever? You have two options, and the choice is entirely up to you.
You can choose to:
(1) be jealous / angry that you missed out on the fun, OR
(2) be happy that your friend is happy.
When you've got that FOMO-feeling, it means you're not present -- instead you're worried about what you missed, regretting that you decided not to join, doubting the strength of your friendship.
But just because they had a fun time doesn't mean you can't have a fun time too. And just because they bonded with other friends doesn't make your friendship with them any less significant.
If you truly love your friend, and I hope you do, seeing them have a fabulous day should give you joy, whether you were a part of that best day ever or not.
There is room in this world for more than one laugh, more than one friendship, more than one epic weekend. Enjoy your life where it is, right now, and then go make your own plans for the next best day ever.