Inducing a positive emotion

This entire week my best friend/roomate and I argued constantly about absolutely everything. I never said thank you for anything she ever does for me and made her feel unappreciated and it was hurting her feelings and our friendship at the same time. After reading your suggested blog from Ms. Armstrong I figured it wouldn't hurt to try writing a letter apologizing for how I've been acting and thanking her for everything she has ever done for me and letting her know that I really do appreciate her and love her dearly. I gave her the letter and received an awesome hug and an "I love you back" and it totally made my day and changed my mood. Following this uplifing incident I sat down to work on the pile of homework I have been letting grow for days. The tasks were not necessarily easier but my attitude about them was better. I still struggled with my math problems but there was something in me telling me that its not so bad and that as soon as I'm done I'll feel better about it. This is definately different than the usual "why the eff do i have to do this" attitude I tend to have about homework on the weekends. I hope to not have to write too many apology letters but appreciating someone or telling someone thank you definately makes their day, strengthens our friendship and makes my day better as well so I definately plan on making this a new tradition.