There’s nothing inherently ‘wrong’ with excitement as it’s a natural part of the emotional continuum we experience as human beings.
In the context of function though, acting on excitement can hurt us because of a tendency to want to do as many things as possible at once, ‘finishing’ today.
Such states are the opposite of the mindful, one thing at a time, in it’s own time, process orientation quality requires.
To close, would say maturity isn’t about whether or not we experience excitement, it’s about internalizing it differently so as not to get caught up in the cascading of distractions that provide a rush in the moment, but ultimately lead to nowhere substance wise.
Side note: The bane of well-intended marketing is getting people pumped about something these marketers genuinely feel will ‘help’ people, not realizing the foundation of what they’re doing is based on eliciting counter-productive states! =)