some of u say to live on forever is to have no more meanings in
life. So i ask: why do u say a SHORT life has MORE meaning to it
than a LONGER life? what is the meaning of dying? what is the
purpose of death? do u really think u achieve anything at all in
death? if u say u get relief in death then i must say u get the
idea wrong - u lose EVERYTHING in death, even the feeling of
relief. Religious people like to think that there is life after
death, well good for you, I'm not going into details about that.
While i agree that there is a chance that an immortal might make it
a habit to postpone deadlines becoz "there is always a tomorrow", i
cannot agree that the main reason why people are motivated is becoz
they "only live once". Do u ALWAYS remind yourself
that you only live once when u are trying to complete certain
tasks, all the time thinking that you are dying as time goes by?
Rather I believe u want to get the sense of satisfaction from the
success of doing it right the first time and meeting the deadline,
or u dont want to do the task all over again. 
Even an immortal might want to meet his "deadlines" and this can be
a motivating factor by itself.
