I think it's the same regardless of the network and is more of a function of how many connections you have: if you have 1000 "friends" odds are most weeks somebody is having an amazing vacation, somebody else is getting a promotion, somebody other is getting engaged, others made a killing on some stock etc. etc.

Of course among those there are also people getting sick, divorced, fired, and so on, but they are not going to necessarily post on social media about it, so your view on what is "normal" becomes more and more skewed and makes you feel worse and worse about what's going on with you, despite the fact that objectively you might be doing just fine.