Truths have truth value while opinions do not.<p>Uncomfortable truths exist. And like all fact based observations they require evidence and are susceptible to disproof.<p>The interesting case is when one takes an internal personal dislike (opinion) and rephrases it as if it is a true property of the world and thereby spreads that dislike. e.g. &quot;all martians are immoral&quot;.<p>More interesting still is when such a person convinces himself that his opinion is based on such &quot;facts&quot;.