My hope is that this position of choosing will allow them to see the advantages of the activities, so that they might decide it would be worth overcoming feeling silly or awkward or stupid. In any case, if I insist, if I answer this question with a list of reasons why they have to, we are in a power struggle where we both lose. When teacher and student are in a power struggle, there is no "teachable moment." The student can win only by refusing to take part in the class, perhaps not coming except to write tests, or perhaps dropping out entirely. I can win by withholding credit, or, in extreme cases, by having him expelled. Both these positions look like winning, and indeed do win the battle, but in fact, they are losing positions as far as teaching/learning goes. The students' right to choose is the only position from which we can both truly win.
Honour it. Welcome it as a sign of students taking responsibility for their learning. Don't get into a power struggle with it.
Before I introduce a teaching strategy that is new to the class, and that I think might meet with resistance, I present it, giving my reasons for thinking it would be valuable. I ask for their reactions, then propose that we try it out for a reasonable length of time, for example, three weeks, and that we evaluate it briefly at the end of the first week, and more thoroughly after the trial period. I make it clear that I will act on the decisions made at this evaluation, and stop using the strategy if most students don't like it or don't find it useful.
If the class agrees at this point to try the strategy out, I explain it in a little more detail, giving an example. I ask the class to predict what effects the new strategy might have. How might it be useful to visual learners? Kinesthetic? Auditory? How might it increase understanding, improve memory, or lead to better test scores? How might it make math class more enjoyable or interesting? All this discussion gives you and the students something to watch for as you begin to use the strategy. At the end of the first week, a brief discussion reminds people what to look for, allows everyone to give an initial response, and reminds everyone that you are trying out something new.
At the end of the trial period, I do a more thorough evaluation. Sometimes I use an evaluation sheet like the one below, and sometimes I ask students to generate a list of questions they would like answered, and turn that into an evaluation sheet, which I administer anonymously and report to the class the next day.
I always keep my part of the bargain—that is, I abide by the evaluation of the class. Why would I force people to do something they believe is not useful and tell me is not useful?