I won't pretend it never happens. But you have to admit there's a contrast between abusing negative emotions (like fear, hate, anger, and distrust) and trying to connect with positive emotions (joy, interest, hope, enjoyment, etc).

If for no other reason that it is much harder to get someone to do something they wouldn't otherwise do while prodding at the positive, but almost easy while prodding the negative. The only times when I can see positive emotions being abusable is sex (as a topic) and gambling, neither of which typically apply to the area we are discussing.