Respectful interactions are very important in a high-functioning classroom. These interactions need to be modeled constantly by the teacher. I cannot expect respect from my students unless I demonstrate it in all my interactions, i.e. with students and adults alike.
My students understand that they do not have to like everything that happens in the classroom (though generally my students seem to be quite happy - see "Testimonials"). However, they also understand that liking or disliking a certain task, assignment, event, or person is something that must be expressed with caution and care. My students and I always work on this, and it makes our classroom communities strong and happy.