Determining Intentions

I do not know if years of management have made me pessimistic about intentions or if I am rightfully questioning of people’s motivations. I think about this in terms of teaching in relation to one of my textbooks, Fires in the Bathroom: advice for teachers from high school students by Kathleen Cushman. This book is excellent in the sense that it gives you a view into the minds of teens with direct quotations from student surveys. As I read some of the quotes, I think, “Okay. That’s legitimate” and then I read the others and think, “You are saying that because you don’t know better yet” or "You are just trying to get your way." I know that as a future educator, I would never use such language or such a definite phrase with a student. . . but I know I will want to. I worry that I may hinder a student’s learning experience by not listening, but on the other hand, I worry that I will be subject to manipulation and that if some students gain and inch, they will keep pushing for miles. How can I always tell the difference between the student who sincerely wants to learn more and work harder from the student who wants the easy way out?