To name a few (note, I am only refering to the loud obnoxious minority, not the majority who are mostly cool)

• Linux: too over the top fanboying a times, and the distro war can be absurd here; this coming from me, a full-time Linux user
• Atheism: yes, I know religion is stupid; but you know what else is stupid, trying to force feed your opinion; I mean, we can't even joke about church wifi name here
• Vegan: no, bashing meat eaters won't make them stop eating them, they'll just hate you more
• American Politic: no, not everything is about your shit, that orange business man/ex-president in an orange suit doesn't affect the rest of the world