Trust me, I am not missing out.
And by which I'm not saying that negatively. You perhaps have a group of friends who are not big social media users or that use Facebook and the like to organise almost every aspect of their social lives.
For me, I would say if I wasn't using Facebook I would be missing out. The biggest thing I would be missing out on would be keeping up to date and in contact with a multitude of friends and family back in the UK where I'm originally from (I live in Australia now).
Sure, there is always email but many friends and family don't use email very much any more and it would be me expecting them to change their habits to suit my preferences.
Know what? May be it does not matter. May be it is a "learned necessity". For example, you don't need to have facebook to keep up to date with all the family members. You just need to call your mom back home and have a chat with her once in a while. Wouldn't you think that would be much healthy way to do this that steals very little of your time and attention?