Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

What is the word or phrase?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

There was an aeroplane crash, every single person died, but two people survived. How is this possible?

You walk into a room where there are three primates held in their respective cages:
1) A lion who is eating the flesh of a goat.
2) An orangutan who is playing with blocks.
3) A donkey who is sitting idle.

Who is the most intelligent primate in the room?

An inspection by the superintendent of St. Joseph School was scheduled on the next day. The class teacher Jenifer knew that he would be asking questions from her class and she would have to choose a pupil to answer. To offer a perfect impression over him, the teacher explained certain instructions to the students to maximise the chances of getting correct answer every time.

What did she say to the students?

A B C D E F G H

These are the letters given to you. Now you have to find out the letter that comes two to the right of the letter which is immediately to the left of the letter that comes three to the right of the letter that comes midway between the letter two to the left of the letter C and the letter immediately to the right of the letter F.

When it's bad luck to meet a black cat?