Being sceptical is perhaps one of the easiest means by which to protect ourselves from silliness, naivety and from being enlisted into the ranks of 'space cadets'.
Scepticism (or skepticism) naturally motivates one to question, to devise experiments, or thought-experiments to test the credibility of ideas. And asking questions is, in my opinion, one of the most noble, useful and valuable tools anyone can possess. It could be argued that a healthy scepticism amongst the populace and judiciary would have seen off some of the more pernicious superstitions and crowd behaviours in times past, such as the executions of those suspected of being witches during the Salem witch trials.
But from my experience the not-so-good side to being sceptical far outweighs the benefits. Being quick to dismiss claims of religious, spiritual, or psychic experience leaves one closed to possibility, and closed to finding deeper congruent frameworks of belief. As I have found, that closed-mindedness can result in quite debilitating health issues.