Depends on the bird. A Budgie can sit in front of a mirror all day happily chirping at its own reflection.
My cockatiel was very tame and spent a lot of time out of its cage. Despite that he chose to walk almost everywhere rather than fly.
They don't need to fly, that's just how they safely...
I've had one. The best thing to do with a cockateil is handle them a lot when they are young.
The more they are handled the tamer they are. A tame cockateil makes a great little pet as they can be very affectionate little buggers.