For those who have ridden a lot of bikes

what characteristics have you found are most important in a bike to put a smile on your face, and make you feel like a kid again?

For example, from watching moto reviews, it seems like bikes with a lot of torque are most likely to elicit hysterical child-like giggling out of otherwise relatively stodgy personalities.

My bike is great, but decidedly not a stupid-laugh inducing bike, and I think maybe I could use some of that in my life.