The illusion of life is a magic trick. Used successfully, it can pull the wool over the eyes of an audience and fool them into believing that your character is alive and thinking. Building a consistant performance can sometimes mean the need for clear rules about who your character is or isn't. There may be a time when you have the funniest gag, but if used on a particular character, can break all believabity.

Please click the pic to have a read!
Making this idea simplier, Jean-Denis Haas has created a nice post on Spungella about structuring the order of a character's thought process. Keeping his advice in mind may help build a more natural performance.
I wish to leave you with this great example from Team Fortress. Its a powerful introduction to a character. By remaining calm, smooth and collective while being attacked by surrounding gunmen presents the Engineer as much more deadly than his appearance portrays.
To watch, please click on the pic. Enjoy!
