I think social media in general is just pointless. Especially Instagram. It's addicting - I know this because I was once addicted to it - but it's just a waste of time, trust me.
People with social media accounts, especially Instagram, don't live in the moment, if you know what I mean. They just take a snapshot and say 'well, that's done'. They don't take time to appreciate what they're really seeing. Say you're at the Grand Canyon (which is beautiful, I've been there). Instead of actually looking out into the valleys and admiring the beautiful Earth we live on, you just take a photo and pair it with a silly caption.
That's annoying. Don't you want to live your life instead of just documenting it with pictures? And that, my friends, is why I hate Instagram (and all social media, really).