Little random things will make me get really upset about my dad.
The phrase "serious as a heart attack" gets on me and I'll get mad if good friends use it - when someone you love drops dead of one in front of you, that phrase just becomes really horrible.  Same with "don't have a coronary!"  
Once I was watching a SNL rerun with my BF and it was the episode from the Christmas before he died, and I just started crying - it just got to me.  
Funny its the little things that sometimes get to me worse than the big ones.  I've been to the church where his funeral was, and I don't think anything of it.  But finding an old tape of his, or seeing a tv show that used to make him laugh tears me up