On the surface, this appears to be an a straightforward question.
However, after one considers the complexity of the human experience, it becomes apparent that the answer could becomes as complex as the question of the meaning of life itself.
There are many variables impacting the outcome of our reasoning on this topic.
For example, do we approach this question considering the investigation from an object to object relational perspective?
Or, Do we examine the question from a precise moment in space-time? Or do we observe the possibilities from the infinite experience along the time continuum?
Do we consider underwear the pair of underwear closest to us in the current moment? Or do we consider 'underwear' to be the collection of underwear that I own at this moment?
As you can see, we have only just begun to scratch the surface of what infinite possibilities may underly this seemingly simple question. The possibilities are almost as infinite as the universe itself. We must be content to accept that this question will remain on of the great mysteries of the universe for which a single response may never be satisfied.