That's a parody of what people actually believe. While this life may be believed to be but a small fraction, it is also believed to have very serious consequences beyond it. There is also the importance of helping others find their way to a "better place." Both of which add significance to this life, rather than undervalue it. Even in reincarnation, your actions in this life have significant repercussions on the next. Otherwise, such a life, or cycle of lives, would be completely superfluous. That seems to be what you think believers actually believe, which again, is complete parody. No believer lives as if they are just passing the time, except maybe in their golden years, where non-believers tend to do the same.