Haha waiting for the bus was the first one I ever saw. Though I didn't know it was cyanide and happiness at the time, I just found the particular short on newgrounds about 5 years ago.
Here is my favorite comic! (Warning: inappropriate content)
Most of my favorite are very inappropriate ones... so I mean, can't really show them here, my most recent favorite they posted that made me cry laughing was the "want to come to my kids dance recital?" one. To say the least one of the words in the sentence has a different meaning...