The past and it's ever lasting effects

I started thinking today about the past and it's effect. I really hate the saying "it's in the past, forget about it" because really, the memories are there for a reason. I was sitting outside for lunch today, enjoying the cold but beautiful sunny weather where I began thinking about my life and how I have become the person I am today, and searching for the reasons why I have got so lost lately in all my problems.
Did I let my past shape me or did I let it define me as a person, or in the most probable sense, did I let all the problems in my life control me and make me lose my inspiration?
An insipiring teacher quoted in one of these special books he presented to me at the end of my 5th year, "Happiness is subjective".
I finally understand it.
I keep looking at other people, looking at what makes them happy and trying to be the same, when really I should have realised amongst the mess, that my happiness is unique, what makes me smile is different from everyone else.
Today I found my motivation again, to make myself accomplish my goals and to find my happiness, and I'll always be there (like my teacher was) to encourage everyone else to do the same.