WHIMSICAL - used to describe someone or something that is unusual, fanciful, and unpredictable.
CAPRICIOUS - used to describe someone or something that gives off unpredictable mood changes or impulsive behavior.
Other terms for FUNNY - laughable, ludicrous, chucklesome, hilarious, entertaining, gleeful, goofy, humorous, and comic.
Other words for THOUGHTFUL - reflective, good-hearted, considerate, benevolent, helpful, deliberate, gallant, chivalrous, mindful, and sensitive.