"enthusiastic behavior" is a correct and usable phrase in written English.
You can use it to describe someone who is exhibiting a lot of energy and excitement about an activity. For example, "The students showed enthusiastic behavior while learning about the solar system."
After a muted reaction to the smaller cut on Wednesday, investors seemed more enthusiastic yesterday, behavior similar to that after the rate cut on May 15.
It was a pattern of enthusiastic bad behavior that, I can only imagine, contributes to the local perception of people like us — urbanites in town for the weekend or an overnight.
Very often, an inclusive relation exists, with enthusiastic teaching behaviors embracing automated expressive components of an emotional experience (Keller et al. 2014).
As the case of climate change illustrates, many consumers are enthusiastic about changing their behavior — in this case, the way they drive cars — if they believe that by adapting to new technologies they will save themselves and the planet.
And when a little old lady does unusual things, like smoke marijuana with her grandson, casually discuss her acceptance of her two husbands' infidelities and remember the good old days as an enthusiastic American Communist, the behavior just seems, heaven help us, cute.
The senatorial committee's chairman, John Cornyn, rewarded O'Donnell's "dishonest behavior" with an enthusiastic endorsement and a big check.
The behavior of an enthusiastic, ebullient 3-year-old with lots of energy can be misinterpeted as attention deficit disorder when it's just a variant of normal behavior".
Think of "Grace" and Aziz Ansari, and the dawning widespread realization that we need a new sexual revolution, one of better sexual behavior, communication, and enthusiastic consent.
Making an effort to be on time shows you are enthusiastic and teachers notice this behavior.
