Of all the things people do wrong in the usage of language, this is probably my pet peeve. Maybe because I believe that I can reasonably argue against it.
People use the term "real life" ("IRL" and, very similarly, "real world") as if it would mean the opposite of "online" or "over the internet" or "using some electronic medium". Hereafter I will call this the wrong usage of the term. It is done so often and regularly that it actually does mean one of these things. Before I describe what I think the problem with it is, let me try to explain what I'm talking about, exactly. Both of those words (real and life) have meanings on their own and using them together is absolutely in line with those individual meanings. I don't find it absurd to expect that the phrase means "the life that is actually true, as opposed to fictional". In fact, I consider it better to expect this meaning because not only did this meaning exist first, it also continues to be used. "The real world" is used meaning the opposite of a virtual world. I suppose the internet was considered to be a virtual world in the beginning and assume that that's where the wrong usage of "real world" stems from.
The main problem that I see is that when people regularly and naturally apply the wrong usage, the notion that the internet is not part of the real world, the real life, is reinforced, which I fear may influence the perception and the expectation that what happens on the internet does not have the same meaning or effects on life as things that happen without the internet playing a major role. In some ways they are (e.g. greater possible audience on social media than on a soapbox), but not in the way the use of "real world" as the opposite implies.
A conversation in a chat room can be much more real than a conversation offline. E-Mails, their meaning and effects on the world aren't less real than those of letter written or printed on paper. A confession over a video chat platform is not unreal compared to a confession over a telephone call, which is not unreal compared to a confession given in close physical proximity, just different. A threat posted in a Whatsapp group doesn't have less impact than a thread yelled at a schoolyard or under four eyes.
I imagine that the more this wrong usage is ignored the more its wrong implications get internalised by society and individuals. I wouldn't go so far to assume that there is a relavant relation between the wrong usage of "real life" and "real world" and the prevalence of "cyberbullying", online harassment and other extreme forms of modern trollship. But I also don't think the possibility that language influences the thinking and by that extension the actions of humans should be overlooked. I wouldn't be surprised if there was some connection to be found. But I don't know of any research on this nor would I expect to find any.