If an arbitrary length of time is infinitesimal in comparison to infinity then it would seem then that it would be absurd to say that any length of time is long or short. So why then do some lengths of time such as a decade feel "long" where as other lengths of time such as a second feel "short"? Length and height are also relative to infinite length but in those cases judgments about how long or short something is can be determined by comparison to different objects but with duration their is no outside reference for comparison. (I hope that made sense.)