Because I have (I was going to say had, but thought that wouldn't be completely true) a tendency to, on occasion, put my foot in it (I know, don't we all?), sometimes I take a wee bit longer than normal to answer a question.
It may be while I work out what the real question is; it could be I'm aware the person speaking to me is a little fragile and I need to be careful how I answer; or it could be I'm trying to work out whether or not they are being really sarcastic. If it's the latter, I need to take that second or too longer to (a) work out whether being cheeky or sarcastic back would be appropriate or (b) decide to answer politely and move on.
This will take a moment. Just a moment, as I try to use a wee bit more sensitivity than I think I need. Okay, so I'm usually very quick at answering, so that may confuse you. But, sometimes, as I am learning, a wee pause to think it better than putting my foot so far in it that it'll take more than half a second to correct.
Of course, this all depends on who I am talking to (and where I am talking to them), the context of the conversation, who else may hear what I am saying, my state of mind and my awareness of the state(s) of minds of those with whom I am speaking.
So, if I pause to think before I reply, don't worry, I am listening. Really, listening and thinking and watching. Honest.