Just last week I've practiced "I don't understand" again. Now I don't particularly like jeopardizing my position at work, but looks like that question wasn't me

Just last week I've practiced "I don't understand" again. Now I don't particularly like jeopardizing my position at work, but looks like that question wasn't met well. A manager running the meeting (plans for next year) frowned upon a person who seems to be not understanding what he was talking before. In retrospect, I might missed some explanations - didn't quite get them at the time he gave them, possibly didn't pay enough attention - but that was the reason for my question! The matter was important to "get". Hard to say if the annoyance was justified... but the result is this question may also backfire, even if it shouldn't.