My DD, then 4.5, cried after her first HM ride. (Yes, after. A little odd). Fifteen minutes later, she wanted to ride again. We did, and she was fine.
This has been her M.O. on HM, Splash and BTMRR, the last two being her most favorite attractions in all of WDW. On her first ride on BTMRR, she started crying halfway up the first hill. I talked her through the entire ride ("Look! A goat! Look! Another goat!"). Getting off the ride, and still crying, she said she wanted to go on it again.
On the second ride, on the way down the first hill, something hit me in the head. I thought it was a bird. It was my DD, then 5, holding her arms up in the air like the teenagers she saw ahead of us. We ended up riding seven times in a row that day. Now I can't get her out of Frontierland.
Len