I'm not a huge fan of the screams, anyway. I much prefer it when peoples jaws just drop and there are few gasps, and everything finishes up with everyone smiling, laughing and thanking me, which has tended to be more normal for my recent (but few) performances.
I think it all rests primarily in presentation. Do an ACR only saying "watch, it's going to come back up to the top", chances are your reactions aren't going to be all that great, though you might get an occasional big reaction from somebody. If you work on the presentation such that it would be entertaining to a degree even if there were no magic at all, then you are onto a winner.
Keep in mind also that some people just don't like magic. A friend of my parents' was over from Ireland once, and he just laughed at anything I did saying "fast hands" and "I don't like magic, it's not my thing". It's a bit of an extreme, but you get the idea.
Huruey