Sure, by not means should you be afraid to play big and involve others. That’s where a lot of roleplay hooks come in. Perhaps, however, you’re looking at playing something a bit more subtle. The game is full of mighty warriors and other people who play big, and a lot of people want to balance that out by going for something a little more low-key – and that’s fine as well.
For a start, even in games like World of Warcraft where the plots are epic and everything is on a grand scale, there are still subtleties and low-key characters that make it work. Think of Little Timmy, trying to get rid of his little white kittens in Stormwind. I’m not suggesting by any means that you are restricted to playing a mighty warrior eager to get into the fray, or a non-combat NPC who spends all his or her time in the city, but this is evidence that it can work. No one suggests that Little Timmy is out of character for the game world, so you should not worry that if you have the vague urge to play a more low-key character that they will fail to ‘fit in’.
Furthermore, there are some classes which suit the concepts of ‘playing big’ and ‘playing small’ to different degrees. Warriors and rogues can equally involve themselves in epic plots, but which are you more likely to see playing big? A warrior is much better to adapt to playing loudly and vociferously than a rogue, where stoicism and subtlety could very well be the watchwords. Not always, but this is just an example.
A gameworld like World of Warcraft thrives on big plots, but big plots require both big, loud people and small subtleties. If nothing else, if everyone is running around and shouting, how is anything going to be achieved? Don’t be afraid to be the person who steps in and everyone ignores behind all the shouting, right up until you fix that one last detail that makes the whole plot worthwhile. Don’t be afraid to play the stoic rogue, the naive priest or even the schoolteacher. There is a place for virtually any kind of character.