Memories from the past

I often think about what for can I thank God in my life. Actually, a lot of things.
But one of them is this privilege to have memories and be able to remember some bright, crazy, funny and even sad moments of my life.
I guess there are periods in all people's lives when the whole days or even weeks pass by, and you don't really live, you actually only exist, because your mind is far away from reality and from what is going on next to you.
I like this feeling. I know it often looks weird...people around make remarks that I look strange and absent-minded/zoning, ask if everything is ok, but I am really ok.
I remember that in the school I didn't have very many friedns, because I was younger than others in my class, I was not very talkative (at least not as talkative as I am know), and I remember there were whole days when I was sitting in my classes, not really listening to what the teacher was talking about, looking at the window or just at my desk and remembering the past...
It happens often nowadays as well - I might be at university class or at work or in the metro or even with friends, but not really there.
I am glad there are spots in my life I like to think over and over again and refresh them in my mind.
The only important thing is not to get too deep into memories, because then there is a chance to miss the rest of this life.