10. Students play along and make applications appear to work even when they don't (to avoid making the teacher look bad).
9. You are taught movements but no self-defense applications.
8. Most of the class is eligible for Medicare.
7. The word "easy" is used to describe any of these three arts.
6. You are taught to turn the hips, not the dan t'ien (sometimes referred to as "waist").
5. You aren't shown how to maintain ground path and peng jin throughout all movements, even in "transitions" and stepping.
4. The teacher says that the 13 energies of tai chi are actual energies coursing through your body.
3. You are told that push hands is about sensitivity, not self-defense.
2. The teacher believes that high level masters (or he personally) can move you with their chi without touching you.
1. The top priority of the class is "chi cultivation."
Now, let me be clear -- some very good teachers hold classes for the elderly that focus more on health and meditation than on the martial aspects, but these teachers also teach the martial side of the art to those who want to learn (or younger classes).
Also, push hands is for self-defense (even though to be good at push hands you must develop "sensing energy"). However, any teacher who teaches push hands only for sensitivity is not really teaching push hands.
If two or more of these things above are true for the class you're attending, run for the hills.