Synonyms:
* Positive: Enthusiasm, exhilaration, fervor, elation, animation, vivacity, eagerness, zeal, thrill, passion, joy, rapture
* Neutral: Stimulation, interest, anticipation, energy, activity, liveliness
* Negative: Agitation, nervousness, frenzy, mania, hysteria
Antonyms:
* Negative: Boredom, apathy, indifference, dullness, ennui, lethargy, listlessness, disinterest, calm, tranquility
* Positive: Peace, serenity, contentment, relaxation, calmness, tranquility
The best synonym or antonym to use will depend on the specific context and the nuance you want to convey.