It's funny how ideas are formed.

What I've experienced has gone something like the 'conversation' shown below. Now, this wasn't a conversation with me. It was the 'other' person thinking out loud to themselves, whilst I kind of stood there! 

You're vegan. That means you don't eat dairy, doesn't it? That means you can't eat chocolate. Oh! I couldn't go without chocolate.

I would not be a happy bunny if this was true but it isn't, so I love hearing this ! Well...I enjoy replying and dispelling this myth!