Definitely YES...GREEN makes me happier and peaceful, it reminds me of Christmas (trees).

They can definitely change your outlook on things, by making you more relaxed, calmer, and putting a little pep in your step! For instance, for myself i find the color orange to give me excited emotions, while the colors lavender and blue tend to make me feel more serene. So to answer your question, my answer would be yes. I would suggest that you experiment with many kinds of colors and hues, and see how one color makes you feel compared to another. I am sure you will have a lot of fun doing it, plus gain a lot more insight into yourself which will serve to further your quest for self-improvement. Happy experimenting!