Quoting from the blog of my ganjie, "happiness is retrospective"...

retrospective... reminds me of accouting terms!! lol!! that is the treatment to correct a previous accounting error and change in accounting policy... change in accounting estimate is prospective...

well, i suppose this applies to life as well, if u realised u have wrongly accounted for a memory as a bad one, once u realised it, u will modify it to become a happy one... if u changed ur whole definition of happiness, then all happy and unhappy events that happened in the past should be re-evaluated, hence, retrospective...

when u feel that ur attitude to a certain event need to be change, u start seeing that particular event from another point of view, thus u change it prospectively...

however, change in accounting policy rarely occurs, so does the change in definition of happiness, most of the time we will just see it as a change in accounting estimate, i.e., we will just change our attitude to a certain event... cannot ignore it as it is against the Financial Reporting Standard...

so if u feel unhappy, just change ur attitude to a certain event, see it from another perspective... this prospective change will make u a happier person...
no, i am not suggesting you to work against your principles as it will then be a change in accounting policy which will then be retrospective...