Two old men were sitting in the park one day talking. One guy said "My son just bought me this great new hearing aid. I can hear everything with it perfectly."
The second old man said "Wow, that's great. What kind is it?"
The first old man pulled out his pocket watch, looked at it a moment then replied "It's about quarter to three."

When I tell someone that I'm deaf they automatically assume I mean "deaf as a post" and then get mad with me if they discover otherwise. The little joke above proves that the man with the new hearing aid is also deaf even though he is functioning in a conversation fairly well. None the less, by definition, he is deaf just not deaf as a post and neither was I until much later in life.