I have a little bit of a problem with how Santa works in some families. The whole "they believed until 10-11 years old, and then I told them and they were so upset."
For me, that means that either your child is incredibly unquestioning (unlikely) or that the parents have been way to forceful and pushy on Santa being real (more likely)
I don't think it is the child's fault. From what I've seen, its more a modern trend of parents creating a world in which Santa IS REAL!" no ifs or buts or possible magic/story telling, he IS real. They see Santa as a kid.. footsteps in the house, no mistakes or slip-ups from parents, he is absolutely real.
Of course a trusting kid will believe it fully.
For me, its much better if you aren't perfect with how you do Santa... there should be mistakes and slip-ups..
Times when you say "last year I bought you" oops... no Santa did...
Oh.. Santa uses the same wrapping paper as mummy...
Huh, the price is on one of the gifts..
Yeah that garden center Santa does have a fake beard
Why are the adults having a giggle/wink to each other when we talk about Santa this year?
Why cant I look in that drawer in December...
etc.
Its all the little clues that they will be oblivious about ages 0-5/6, but then from around that age to 8-10 they will pick up on it more and more, and naturally question it, and gradually come to the realization of what is going on. You never need to have the "chat", they just learn it on their own, and "play along" because they have learned what the game is now...
But that would be ruining the magic for some on here. Better keep them in the story completely until 10, not give them the chance to use their brains, and then break their heart when they are older.