Life is never ending, whether you're there to live it or not. It's also non-stopping. Sometimes you just have to stop yourself while life goes on and just close your eyes and remember. Remember the past. The days with friends. The school days. Every detail matters. You close your eyes and say out loud (or not) "Oh yeah I remember when I did...." or "she/he did this..." You may start to cry. You may not want to remember somethings. But EVERYTHING THAT HAPPENED IN YOUR LIFE MADE YOU WHO YOU ARE! Whether you're strong, faster, smarter, wiser, etc., Every single thing that has happened in your life made the person you are.
I remember many 'bad' memories/situations. Some filled with depression. Some with anger. Some with anxiety. But ALL of them made me much stronger mentally and emotionally, wiser, and more aware if such situations ever happen again.
And amazingly enough, I wouldn't want it any other way ;)