I.E. versus E.G.- respectively, they literally mean "id est" (it is) and "exempli gratia" (example's sake), respectively meaning "in other words" and "for example".
Democracy versus Republic- America is not a democracy. We are a republic, which has inherent elements of democracy, and we have instituted more than just the barebones, but we are still a republic. We pledge allegiance to the flag "and to the republic for which it stands". Goddamn.
Socialism versus Communism- not at all the same thing. Socialism is an economic theory, communism is a social, political, and economic theory that usually encompasses socialism. But it isn't socialism.
Ask versus Axe- just, fucking damn. Speak english.
More of a pronunciation thing, but when people say "excape". That isn't even a word.
As severally stated before, "irony". It's not what everyone uses it to mean, though it can encompass that meaning.
People who say "harikari" annoy me. It's "harakiri".
The word "nucular". If you say that you should be punched.
The double-is phenomenon sweeping the country. If it's in a relative/subbordinate clause it's fine but really nowhere else. You can say "what this is is" because "what this is" acts as a single grammatical unit. But saying "my point is is" is wrong and stupid.
People who say "lol" or "rofl" or "stfu" out loud/in actual, verbal communication and use them seriously. It taps into the deepest wells of hatred within me.
Inflecting your tone for a question whenever you pause in speech. It just makes you seem retarded.
The word "bro". I fucking hate the word "bro". It should not exist.