I don't remember ever actually thinking that he was real but I do remember imagining him walking through the wind and snow to deliver the presents. 

I never thought he was real but I never thought he was not real ether. I always said I didn't believe in him but I would still write him letters every year, and get surprised how he guessed what I wanted for Christmas. I didn't believe in him but every year as I got my desired present, I would question his existence and start to think he might be real. 

And with all the Christmas movies every year, who wouldn't want to believe in Santa Claus? But one year I was misbehaving some time around Christmas and my mother told me that If I would misbehave, Santa isn't going to get me any presents. I was a wild child so I didn't care and my bad behavior continued  until Christmas day. 

When I woke up on the Christmas morning, I was feeling grumpy and rebellious. I knew that I wasn't getting any presents that year so I was mad and sad at the same time so I decided to apologize for my behavior in the past few days. My parents were forgiving, but so was the "Santa" apparently.  Even though there were no presents addressed to me under the tree in the morning, after my apology, they magically appeared. 

That was enough to conclude that he is just not real, and the Santa is actually my parents.  I wasn't heartbroken because, like I said, I already had some doubts. I think I was 7 or 8 at the time, or maybe 9, I don't really remember.