The ages of 18 to your mid-20s are a very dangerous time in a gamer's life, because you're basically on your own for the first time, with no parents or teachers around to tell you to stop playing videogames all the time. Since you're on your own, this becomes a formative time in your life, as you try to figure out who you are and what your place in the world is. But the problem with this is that you're forming a lot of habits for yourself at a time when you've basically got all the time in the goddamn world. And, if you're like me, this brought you to a very dangerous place...
Before you know it, you'll have some combination of a career, family, friends, pets, and kids. All of these can be rewarding, meaningful things that will fulfill you on a level that almost nothing else can. They're also all enormous timesucks, and all of your free time will evaporate before your very eyes. And that's why getting SUPER into RPGs in your early 20s is a mistake.
Whether it's JRPGs or CRPGs or...well, basically ANY RPG, the game represents a thing that is just gonna steal 60-100 hours of your life like it was nothing. When you've GOT that kind of time to burn, it's great - you can get lost in the world and immerse yourself in this fun, weird adventure, because you're only taking 12 credits this semester and don't even have class two days a week.
When you've got a job/spouse/kids/[any other kind of adult obligation]? It's a problem. A big problem. A new RPG coming out is like knowing you have a major project due at work soon, and it's gonna take a ton of time and effort to finish up. It's something you HAVE to do, not something you GET to do.
Basically - say so long to sleeping more than 4 hours a night for the next few weeks, since midnight to 3am is the only time you have available to yourself to play your fantasy-world RPG.
When you finish other major tasks in life, you'll usually have something to show for it - projects at work are things you can bring up to your boss when you want a raise, projects at home result in a spiffy new shelf or some home improvement (that ended up being a lot harder than The Sims would have you believe). But an RPG? Well, I can tell you LOADS about the Daedra in Tamriel, but the problem is not a goddamn person in the world gives a shit.
I have more accumulated worthless knowledge from a variety of fantasy worlds than actual knowledge about the real world - and even people who've also played the games I've played usually don't wanna hear about it (seriously, go ask someone who just played Skyrim if they'd like to discuss the downfall of the Dwemer).
All that knowledge, all those journals you've read, all those stats you memorized...totally worthless (except for editing wikias, which is another thing you should probably keep to yourself).
It's hard to say which is worse for a person, socially-speaking - a single-player or online RPG. With single-player RPGs, you are forced to COMPLETELY withdraw from social interactions if you want to play (and most are NOT the types of games you can pick up for a few minutes here and there between commercials - nope, most are the types of games you'll want to sit down for 3-5 hour chunks). That means no going out at night or on weekends, and barely seeing/interacting the people you LIVE WITH.
On the other hand, there are online RPGs, which teach you a form of social interaction that's pretty much the opposite of how you should interact with people in the real world.