I'm not sure if there's anything that annoys me as much as people who 'know' what I'm thinking.
You know the ones. They look at you and laugh that you're just dying for the weekend to begin, you're thinking about what to have for lunch. They think you want to have a long extended conversation with them about their family problems, you're thinking about how you're dying for the weekend to begin and how far away it seems right now.
They are offended that you didn't tell them something because you were feeling guilty about it. You felt it was none of their business and were actually concerned about someone else at the time.
They know that when you smiled when you said something - it meant it was all about you. You smile and correct them, but they wink knowingly. You know that when you say "my friend...", you mean "my friend..." .
I don't know why people continue to assume what I'm thinking, because they're so frequently wrong. But what I find offensive is when people assume what they're thinking to be true without actually asking first, especially if it is something significant. My high school English teacher always said when you assume you make an 'ass' out of 'u' and 'me', and it remains a motto for me. Never assume anything. And so I ask questions, a lot of questions. Break things down until I can break them down no further. Of course the answers I get aren't always the truth, but then if I get it wrong - it's not completely my fault. But when people assume things of me these days I tend to let them assume what they like. They might think I'm evil, or scheming or whatever, but who am I to correct them.