You know why people cannot seem to find happiness? Because they don't realize that happiness is not a destination. You cannot keep telling yourself, if this happens or that, then I'll be happy. The Universe is always providing you with reasons to be happy but you're stubborn. So you don't want to take the chance and just be happy!
If you talk about on very personal terms, I have a list of things that can always make me happy no matter what I might be currently going through in life, (and in no particular order as such):
1. My mother
2. All my cats
6. Soul Mates
If you're feeling sad, just make a list of all the good things in your life. No, you don't get to be pessimist and tell me that there's nothing good in your life. You will have to learn to dig deeper and tell me what makes your life so uniquely yours.