I think of the learning environment as similar to parenting. You have to be supportive of the students so they can learn and make mistakes, but you can't be their "pal" and give them what they want when it's not conducive to learning. I find that faculty I've had or worked with sometimes try to cater to the students so much, they've just cut the student's learning experience. I think having clear, consistent, and appropriate expectations make a positive learning environment where both students and teachers know what their roles are (even if the outcome is negative i.e. bad grades).