You've got 24 hours in your day just like everyone else. There is a definite relationship between students who do poorly on tests, receive low final grades, or fail courses, and those who turn assignments in late. Being courteous in class doesn't mean you have to agree with everything that's being said. When asking questions, don't be hostile or demanding and don't back the professor into a corner. When you disagree or don't understand a point, be positive.
Grades are another area in which professors and students sometimes disagree.
Never discuss a grade when you are angry. A test may have seemed to you to have been unfair, but don't label it as such when you're discussing it with the professor. Be specific but courteous when making you points. Remember, regardless of how skillful you arguments are, the odds are that your grade won't be changed on that particular test. But, if you make your points well, the next test may be much better constructed and may seem to you to be a fairer measure of your knowledge of the material.