Is it correct to say that, using "most of all" or we have some better choices to ask such question?
What do you like most of all in school/at work...?
You could use "most of all" or "best of all" if you want someone to respond with just one thing that they like most/best.
If you ask what people like best (or most) about something, they may list a number of things. A group of things can be described as "the best", for example, an album of songs may be titled "the best of [artist]" because all of the songs on that album are among the artist's best work. By adding "...of all" you are soliciting just one response - the best of the best.
Another way to do this would be to use the definite article and ask:
What is the best thing about school?