Dr. Julius Hibbert is the most promient, competent doctor featured on The Simpsons.  If we wanted to talk incompetent, we'd be talking Dr. Nick!  Hibbert is very good nature and always laughing.  Good guy.

Dr. Hibbert Quotes

Dr. Hibbert: You have twenty-four hours to live.
Homer: Twenty-four hours!
Dr. Hibbert: Well, twenty-two. I'm sorry I kept you waiting so long.

Dr. Hibbert: Um, your wife agreed that I should break this to you.
Homer: No need, Doc. I can read Marge like a book. (Looks at Marge, who is very glum.)
Marge: Hmm.
Homer: Ooh, it's good news, isn't it?

The Simpsons Quotes

(Bart shows the whole classroom the tape for his project called, "How Kittens Are Born: The Ugly Truth")
Bart: and here comes Snowball II. This is the one we kept.
All: EWW!!
Bart: We were gonna keep the gray one, but the mother ate her.
All: EWWWWW!!
Martin: Mrs. Krabappel, he's traumatizing the children!
Mrs. Krabappel: As usual, I agree with you, Martin. Bart, shut that off and take your seat immediately!
Bart: Oh, look! This is really cool. When I hit reverse, I can make 'em go back in.
(The whole classroom screams)

Homer: (Wearing glasses) The sum of the square roots of any two sides of an isosceles triangle is equal to the square root of the remaining side!
Man: (From inside a bathroom stall.) That's a right triangle, you idiot!
Homer: D'oh!