Lying is being loyal to the person who told you to lie, but not to the person you’re lying to.
Some strange people often say something, and then end the phrase with “but this is just my opinion”. But don’t they want their opinion to be true?! Why say something without being certain about it? Why bifurcate the reality to a subjective “everyone has their own feelings about it”? Humans are different, but not to the point that there are alternate truths and realities.
When I say something, I am certain that it is true, whether it is so or I want it to be. Obviously I won’t say anything if I know what I say isn’t true.
P. S. If there is uncertainty, just say so.