Attitude (noun): manner, disposition, feeling, position, etc., with regard to a person or thing; tendency or orientation, esp. of the mind: anegative attitude; group attitudes.
We all have those days when our attitude can get in our way of our experience. As a teacher I have experienced the attitude of disappointment, resistance, fear, and uncomfortableness from participants when I am subbing a class. I have also been the participant of walking into a class to find that my normal instructor is not there and feeling those same attitudes in myself. When these feelings arise from either end I try to take a deep, cleansing breath and change the direction of my disposition.
After taking a deep breath, if I am the instructor I try to break the ice a bit and acknowledge that I understand how difficult it is to have a different instructor but hope that they will remain open and exploratory through the process. If I am the student I instruct myself to stay open and remember that even if I take away one new idea, movement, or connection from this instructor that the class was a success and worth it. Changing this attitude allows the experience to change. One of my instructors stated awhile back "that if you are going to a led class, then you should allow the instructor to lead and teach you and leave your preconceptions behind". You may be surprised at your experience and what you learn if you can change your disposition and remain open to what is being presented. You might even find a new teacher that you never would have taken class from and now adore.