being told that something that I know is good for me (or which I believe is good for people I care about) is actually evil and needs to be destroyed, especially when such a denunciation is devoid of any solid evidence, and most especially when I have spent a good amount of time pointing out counter-evidence, and that counter-evidence is completely ignored.

being told that what I believe is actually just something I’m mindlessly regurgitating, instead of something which I have thought about at great length and researched quite deeply, especially when the person doing this doesn’t really know anything about me, and is basing this idea on some ridiculous stereotype, and without any supporting evidence.