|The time to respond to this type of comment is when it occurs, and it sounds like you have taken care of that business already. If you go back and say anything further, you will be turning a few words into a war of words. You need to pick your battles, and this situation is strictly plowshares.|
Your boss's comment can actually mean just about anything, depending upon him, you, and your working relationship. For example, your boss may one of those clueless individuals who wander around making inane comments to the employees without really knowing what is going on, or perhaps he is just an upbeat and humorous chap who was teasing you in good fun.
Similarly, it's possible that you enjoy teasing the troops and he was giving you a little payback, or perhaps you do spend too much time gazing into the great beyond. Either way, it's important to take a look at your overall relationship and place his comments in context.
By understanding your working relationship, you should not have trouble thinking of an appropriate response if there is a repeat performance. Just don't spend a lot of time staring into space as you think about all of this.