He always came uninvited.
He always tried to ruin and destroy Laura's love life. Sure they were not good men but Urkel would never accept Laura with a man.
He would guilt trip Laura every chance he got. Why don't you love me. I am sorry. You are mean.
In the end I think Laura developed a sort of disorder and fell for the worst person. He will never let Laura go and will be on the news for committing a crime of passion