I propose a challenge, and I myself will be trying this out as well; your challenge if you choose to accept it is to write five things that made you happy that day in a journal entry.
Your first entry may take some time, but be patient with yourself, after the first few entries it will become second nature.
It has been said that such positive thinking and being thankful for daily blessings will improve your appreciation for life, and as like attracts like you will notice that your overall energy will change and you will become more positive and peaceful.
Let me know what your experiences are with this! I can't wait to hear all about it!