You never know what someone else is going through. Someone could be having a rough day or week or month or whatever and even though it may not seem like it's that bad to you, you don't ever really know what's going on behind that facade.
Not too long ago a friend of mine posted that they had had the worst week of their life on Facebook. This person got all sorts of virtual hugs and comments meant to comfort them. Then they got one that said something along the lines of "I don't know why your week is so bad but if you are glad that you spent time with your family, then it can't really be that bad." This dismissive comment just burned me up and over a week later, I'm still thinking about it.
I know why my friend posted that, and that it very likely WAS the worst week she has ever had. I have had this happen to me before when I've posted that I've have a bad day or something too. That you should just be grateful for what you have. Way to invalidate feelings lady. You never know what is going on behind the scenes in someone's life and posting something like that is incredibly disrespectful and rude. It's like the whole just be glad you have a healthy baby line. It doesn't matter that something horrible happened, just be glad for what you have. Of course you're glad but your feelings about a specific event are separate and you can feel however you want. And those feelings are valid.
I didn't respond to that person on my friend's post because I didn't think it was my place nor did I want to start something, but I really hope they felt like a jerk when she finally posted what had happened.
Maybe next time you are tempted to say something you should just keep your mouth shut and keep on scrolling. Because you never really do know.