I personally find enthusiasm very endearing as long as as the object of enthusiasm isn't being shoved down my throat,

I am in total agreement with you there. There is an appropriate time and place for being fannish.

I think people often confuse enthusiasm with immaturity or childishness, which just isn't the case. You can have a child-like sense of enthusiasm, imagination, and joy in life without acting childish (ie. shirking responsibility, throwing temper tantrums, etc).

It's sad that there aren't more people that act that way, since, in essence, you are combining the best parts of childhood and adulthood.