"Bad Bob" joke

One day, Bob's class was assigned to write down everything they heard at home.
When Bob got home, he heard his mom and dad fighting.
"Shut up" he heard his dad say.
Bob wrote that down.
Next he went to his sister's room. She was chatting on-line. It just so happened that she said everything she typed. "Duh!" Bob heard her saying.
Bob wrote that down.
After that, he went to the living room were he heard his little brother saying, "Super Man!"
Bob wrote that down.
Last, he went near the bathroom were his grandpa was singing, "Every day, the whole day, in the bathroom."
Bob wrote that down.
~~~
The next day at school, The teacher asked Bob, "What did you write, Bob?"
Bob answered, "Shut up!"
"Excuse me, but do you want to go to the Principal's office?"
"Duh!" was Bob's reply.
At the principal's office he asked Bob, "What's your name?"
Bob answered, "Super Man!"
"Uh huh, and where do you live, Mr. Super Man?" asked the principal.
This was his reply:
"Every day, the whole day, in the bathroom!"
From that day on, Bob was home-schooled.
P.S. I know it's a lame title, but what can I say, I'm not brilliant when it comes to titles.