It's interesting how you can almost completely forget about something that or someone who used to be such an important part of your life, and yet it doesn't take much for you to suddenly remember all about it/them.
Here's an excerpt from a letter written by Marcel Proust in 1913 that I came across not that long ago.
"So we don't believe that life is beautiful because we don't recall it but if we get a whiff of a long-forgotten smell we are suddenly intoxicated and similarly we think we no longer love the dead because we don't remember them but if by chance we come across an old glove we burst into tears."