This topic came into my head and honestly, as I thought about it I read the other topic "What makes you nostalgic".
So, what makes you sad? Could be anything from what people do to you, to the people around you, what you have done in the past that you regret, what happens in your day to day lives or even a single event that has happened in the past that continuously comes back into your head and just causes a great amount of sadness.
One thing that makes me sad is that I drive across my city almost every day and I pass by my grandma's apartment building who passed away in Feb of 2011. There's no way I can not see the building. Every time I pass by I say something in my head to her, which I know she hears.
