what would I miss out on?
more importantly, FOMO, when applied to real relationships, leads to this utilitarian mindset where you view other people and your interactions with them in highly objectified ways, centering the possible opportunities your relationships with others might provide. other people don't exist for your benefit. this is a form of non-sexual fetishization, where you start to view actual people as tools and grant those tools metaphysical power over your life - not interacting with them might lead you to missing out on something /critical/.
treat people like people. spend time with people because you like them and enjoy your time with them. don't fixate on your own ends and make means of other people.