Teachers are people too. Consider that you have favorites. Favorite foods, activities, friends, maybe even family members. Why do you pick those things and people as your favorites? Most teachers do not choose students for specific tasks because they are that teacher's favorite student. Some may, but most don't. That you believe they do is more about perception. Does that make sense? You believe teachers pick favorites, so for you it is true.
Something else to consider--those who try the hardest to be recognized usually aren't. Most people prefer humility. Sit back for a while and watch what the other students around you do, especially those favorites. :) Focus on what you do well, and you will likely be chosen to demonstrate it.
If this sounds like a "teacher answer," it is because it is. Teachers do find students they enjoy having in their classes. All for different reasons. I have. And, I, like most of the teachers I know, work very hard to not show favoritism. I spread the wealth. Usually I pick students at random.