While the point about open voting for government representatives is well taken, I would like to suggest that @flo‘s worries are not completely baseless. The bandwagon effect is a well-established cognitive bias, and the Asch conformity experiments show how powerful the pressure to conform can be.
In an antagonistic environment like the political arena or a debate society, the pressure to conform is dissipated by the fact that it is already known that each side has support. Outside of such an environment, however, the results can be disastrous. The Challenger disaster, for instance, is typically attributed to the problems of groupthink.
What, then, is the solution? Asch’s experiments show us that the presence of even one dissenter significantly reduces the pressure to conform. Many people will not themselves become dissenters, however, unless they have a confederate. The lesson, then, is this: be the confederate; help others to express their dissent.
It can be uncomfortable to be the first dissenter, of course, but the overwhelming likelihood is that you will get allies in short order. For as @Ron_C notes, human beings love to argue once given license to do so.