Tough question with a very simple answer (for me anyhow). Like you, things are pretty good in my life at the moment, so being in a "funk" isn't something I tend to think about all that often (lately). I have many good things in my life to be thankfull for, and many not so good things that I "desire" to change. There lies my answer - any of the "not so good" things that affect me in a negative and noticable way , will receive significant effort to change them. There in also lies a sence of accomplishment and gratitude, giving me the happiness I was seeking...
I guess in a much less philosophical way I could have just said - see a problem, do what ever you have to to fix it, be happy about it, move on... :) Cool post... Steem on...