Creating a character in a videogame as completely as I do in an RP? Nah, doesn't happen for me. With an RP, the OOC usually has all the tools I need to really understand the world and create a character for it. Most of the videogames I play like to hold back on those kinds of details, so I can't really envision things like where they were born, or even the type of environment they might have grown up in. It can also be quite jarring when you have a story figured out for your character, and the game throws one of those "but you are the chosen one!" things at you.

When it comes to dialog choices and getting skills, I do tend to think about things like what my character would say/do/have in that particular situation. but even here, some games will punish you for not making "smart" choices. So I find myself overriding choices my character would make just so that I can get the stuff/side quest/complete the game.

Of course, it wouldn't be hard for me to add more detail to these characters. it just never really works in game.