If you're excited you're enthusiastic and animated, like a kid in a candy store. Or a kid on Christmas morning. Or a kid on the last day of school.
Meaning more than just "wildly happy," excited describes all sorts of excessive emotions (and not always the good ones). If you're excited you might be agitated, nervous, anxious, or worked up about something. Skip a little further out on the excited spectrum and you're verging on a loss of control: You're delirious, frantic, mad, or unrestrained. Less like a kid in a candy store than a kid on his tenth cup of espresso.