bj, that's hilarious, but wonderful if true!
Yes, Denise, suggestion can be very powerful, and not just in teaching. Advertisers rely on it. There's this whole thing about you're not selling some product, you're selling some promise. So you're not selling Pepsi, you're selling the idea that if you drink Pepsi, you'll be cool, you'll have fun. You're not selling a car, you're selling the woman who (in some guy's fantasies) is posing next to it.
I think a person has to be open to it, even if subconsciously. Students already see the teachers as knowledgeable, so they're open to accepting most of what the teachers say. So teachers have real power to do damage with statements like the "everyone will do badly on this test."