I get annoyed at friends who refuse to use Hangouts
I don't know why but I have a number of friends/family who want me to use WhatsApp, WeChat etc and simply refuse to use Hangouts. And these are people with (mostly) Android phones who all use gmail. I tell them its already on their phones, they already have an account, there's nothing to do except start using it, and they are still resistant.
Hangouts is just so much better and nicer to use because its everywhere. I don't want to unlock and type on my phone when I can use my pc instead, and have everything sync up. Its true integration unlike the islands in each of these apps. I've had a friend upgrade her phone, she lost all her IM history and didn't care about it, which I don't get.