Facebook Messenger does a lot more than just open every time you want to reply to a message you're trying to open on the Facebook app. Really. To get up to speed on all the features you've likely never used, check out this video.
CNET shows off how to make those blue messages pink, or whatever color you're into, and how to add photo captions using Messenger. Additionally, the clip points out how to play games on Messenger, order an Uber, and a few other hidden features that make it way more useful than just sliding into someone's inbox.
Watch it and become a Facebook Messenger pro. And then you can go right back to stalking people.