Question: Sometimes, when we say "Nobody wants me to do what I don't want to do？", I was always wondering and dying to know if I could say "Nobody wants me to do what I don't want to" instead? Thanks.

Answer: 
In English, there can be ellipsis of a verb clause.

**Nobody wants me to do|| what I don't want to do||**.

In this case, you cannot leave out the do. Because there is a complex sentence made up of a main clause and a subordinate clause. 

You can only leave out **repetition of the verb that comes after to when the context is clear**. That said, some people in speaking might very well leave it out: **Nobody wants me to do what I don't want [to do]**.

Person One: I **want you to go** to the movies with me.
Do you want to? [you can leave out repeating go]
Person Two: Yes, I want to. [to go to the movies, implied]

Person One: I want you to do this, I insist on it.
Person Two: Why do you want me to? [to do this].
British English is much more likely to include the *do*. Most Americans omit it whenever we can get away with doing so, and would probably prefer the "Nobody wants me to do what I don't want to" form.