I dig yellow. I think it’s a great accent color plus it generally makes people feel happy. However, too much yellow can make babies cry and cause adults to lose their tempers more quickly. It speeds up your metabolism (good thing, right?) but can make you feel cautious. Remember the short story, The Yellow Wallpaper by Charlotte Perkins? Makes me a little apprehensive about using it too much when decorating.
http://interiordecorating.suite101.com/article.cfm/using_yellow_in_design