I was off last week giving a talk at another department's weekly colloquium. I gave my talk, and was shocked to find that every question was prefaced by 30 seconds of thanks for the talk, then a word or two about what each questioner found especially interesting in my talk, and then a question. I found this unbearably patronizing, but when I interrupted a questioner by saying "You needn't thank me. Just ask your question," it was taken to be an expression of politeness or gratitude. What a waste of time. Thank me for the talk by asking a hard question.
Then on Wednesday I attended my own department's colloquium, and noticed a different vice: questions were preceded by long (sometimes a minute or more) build-ups intended to clarify the "context" of the question. Sometimes the build-ups seemed to be unrelated to the question. Sometimes the question seemed unrelated to the talk. Sometimes no real question was asked (after the build-up). It's hard to know what to do to remedy this-- I suppose one cannot simply say to one's colleagues that they need to learn how to ask a question (or pay closer attention to what the speaker actually said).
When I was a graduate student, my department had pretty strict rules concerning colloquia q&a: a moderator kept a list of people who wanted to ask questions, grad students were always placed at the bottom of the queue, and those with bad q&a habits were never allowed to ask the first (or second) question. This seemed to me then problematic, since it required the moderator to implicitly express judgments (often unflattering) about his colleagues. But maybe there's no better way to keep things on track? Any ideas?