Most of the above grammar-related offenses bug me. But they bug me five times as much when I see them on CNN's website, in the New York Times, or in corporate materials, or in important personal correspondence. I'm trying to relax about bad grammar in informal speech and informal writing. But in more or less official material, I can't stand it.
My grammar isn't perfect by far, but it's probably better than 99% of native English speakers.
An aside: my boyfriend has a big brain. He has degrees in math, chemistry, business and law, and is a mostly wise and well-spoken person. But when he's relaxed, he likes to use bad grammar sometimes. I hate it. I think it makes him sound dumb, and he's not dumb. Not only that, but I think his doing it makes me sound dumb too, by association. He's actually asked me to let up on correcting him. He says he's expected to speak properly all day at work, especially in court, and he likes to let it go a bit when he's relaxed. Of course I think that speaking badly is less relaxing because it's dissonant and requires more effort to understand, but he doesn't see it that way. Since he almost never complains about anything, and tends to put up with a lot, I have to conclude that my correcting him bothers him a fair amount since he took pains to bring it up. So I'm gritting my teeth and not letting the sounds escape my mouth when he uses bad grammar. I have just asked him to please never do it around my parents :-).