The first is easy to answer - it is because the act of remembering takes place in the author's present that is at the time of writing.
The second is more difficult to answer. The author probably strongly believes this was a lesson for life and that it still holds true for him now (his present again). If he had used 'wanted', it would make it more remote and might suggest he was a little embarrassed by this belief or perhaps that he wants the reader to understand that he has since modified his behaviour/opinion. I'm not sure everyone would agree with me on this though.
Interested in Language