Different facets in different environments
I've mentioned many times that not every part of your character backstory is of equal importance. It may turn out that the group you wind up playing with in Star Trek Online isn't interested in your character's history with Section 31; his childhood on a starship is far more relevant to the current situation. If you're creating a nice and detailed history, this isn't a drawback since you have plenty of details that might shed more light on the character's motivations even if no one else sees them on a regular basis.
But if you're playing the same character in several situations with the same core elements, you'll get a chance to see many more character elements come into play. A trivial background element in one game is important in another game.
Rhio, my hopeless wanderer across games, has always been a linguist. In Final Fantasy XIV, this was more of an interesting curiosity than a major character trait, as the language that was actually relevant to the plot was one she didn't know. In Guild Wars 2, it's actually far more significant, as she does know some plot-relevant languages that make her more useful than she would be otherwise. In World of Warcraft it never even came up, but her experience with potions and the like was relevant, though it's yet to come up at all in Guild Wars 2...
You get the idea. If your character has too many plot elements to fit comfortably into one story, having multiple stories allows those elements to rotate in or out as necessary. In one game his romantic streak is important, while in another his love of adventure makes a difference, and in yet another his deep bias against pudding has a big impact on roleplaying. It all depends on the environment.
New experiences let you learn more
No matter the game, Rhio has been trained as an assassin. In every game where this had come up, she has always been very reluctant to mention it to others, so I have always assumed in the back of my head that this was something she found shameful. It was only when I played her in GW2 and she started mentioning it more often that I realized she didn't find it innately shameful. It's a matter of that fact being at odds with who she wants to be, and in the company of mercenaries, it's actually a useful bit of her past to make public, but she keeps it far more quiet around people she considers to be peers.
A good character will speak to you but not always in a clear voice. Sometimes you'll know what your character should do without having a full idea of why, and it's not until you've played the character in different situations that you understand all of the reasoning behind a choice. Having more than one environment helps, but having a flat do-over for a character concept can sometimes make certain issues clearer.
The net result is that after you move to another new game, you know more about how the character will act right from the start. That lets you direct yourself in different ways, and it means that you can have a clearer of picture of what will happen in any given environment. It also means you have a more developed voice for the character as a whole, one that serves you well when you're starting back at the beginning.
Familiarity breeds confidence
Roleplaying is hardest right after you start a new character, and not just because you still haven't found that character's voice. It's because your new character may very well be stupid.
Creating a stupid character is nothing to be ashamed of. I've done it, you've done it, pretty much everyone who's ever roleplayed has done it. But there's a certain amount of apprehension involved in creating a new character no matter the concept because you can't help but worry that the idea comes off as stupid. Especially if it pushes some of the boundaries of the game as a whole or if the concept requires a certain amount of hand-waving to accept. Or if you're trying to use one of the endlessly repeated cliches of bad roleplaying in a positive way. You get the idea.
A familiar character in a new setting still breeds some of that apprehension, just less of it. You know what parts of the character worked right last time and which ones didn't, so you can surreptitiously excise problems. You can also roleplay with the confidence that if the character idea is dumb, it would have become more obvious by this point.
I know the weaknesses of my recurring characters. Some of them can come off as being perfect at everything in the wrong situation, some of them are difficult to engage in conversation, and some of them lean pretty hard on the wall of lore. All of them are characters I've played before, ones I can work with as necessary. I can deal with those faults, and if people receive them badly, I know better how to address matters.
And it's also true that I really enjoy playing some characters time and again. So that helps, too.
Feedback is welcome down below as always, or you can send it along to firstname.lastname@example.org. Next week, let's look at a few common mistakes that lead to less interesting characters and how to head them off before they come up.
Every Friday, Eliot Lefebvre fills a column up with excellent advice on investing money, writing award-winning novels, and being elected to public office. Then he removes all of that, and you're left with Storyboard, which focuses on roleplaying in MMOs. It won't help you get elected, but it will help you pretend you did.