Some might believe that the only paradise is the paradise lost. Our rosy memories of where we've been - travels, high school/university, living situations, relationships, and more. How many times do you hear something like "I remember that time in my life. I had no idea how good it was at the time..." with the unspoken final ending of "and now it's forever gone."
Well, screw that. Fondness and being sentimental are good - the past is a big part of who we are - but it's possible that you might say the same thing about right now.
FYI - apparently it's a quote by Marcel Proust, but I read/heard it elsewhere..!