I'm chronically ill, but keep a lot about my illnesses off of SM because my healthy friends have made assumptions about my abilities (or lack thereof) and have left me out of stuff thinking they were being kind.
I also have a lot of chronically ill friends. Their posts don't bother me, unless they're moaning about not being able to do anything around their house/go out/work, then post that they've got a better social life than me. Another posts a fully made up and hair done selfie every day, captioned with how ill and rubbish they feel and look. Well, if I'd put on a full face, clip in extensions in AND curled them just to do the school run I'd be needing a rest too! When I was having a bad day when DS still needed taking to school I considered pulling a tracksuit on over my PJs and brushing my hair a win!
I have one friend I've had to mute because everything on SM is picture perfect, but I hear from my DM (who is friends with her Mum) how IRL everything is falling apart. On SM she's married to her best friend, has beautiful children and a thriving business. In reality her DH is no help financially, with the kids or round the house, both kids have health issues (but she and her family have a long history of treating anything less than perfect as shameful) and she's having a breakdown and not wanting to run her business even though it's the family's main source of support. I can't deal with the discrepancy and find it easier to be sympathetic when not constantly bombarded with #blessed posts.
Many of my friends have reached the having DC stage (I had DS comparatively young) and suddenly they're all trying to be SM influencers. Lots of formulaic posts about products they love, photos of every healthy meal they give their kids or themselves (along with weight loss journey tags) and competitive mothering about parenting styles and mum guilt. I sit there like "Just WAIT until the teenage years!" 
Lastly the "friend" who constantly posts about things that make her heart hurt which are all thinly veiled "look how caring and humble I am" type posts when she can be one of the biggest bitches ever. And I can't mute her as she is a big part of my hobby group and I need to see her posts about that!