People leave. That's a reality. 

Whether it's a lover, or a friend, or even just a buddy you've met and had a feeling you would be close with, but never actually did. But you know what? People also come back. One day, when you're walking down the street, thinking about your own little problems, something or someone will remind you of that person, and when that happens, you will always remember the good things. Yes, you will also remember the bad things, but when people become significant in your life, it probably means they did something to cause something good in your life. So to that person, or those people who have left, or who will leave, I would like to thank you for your significance in my life. You have been a great lesson at this moment in my life.