Tsk.
But think about all the amazing things we do, too.
It's human to be able to take what is ultimately a meaningless, finite project (living, existence) and not simply make it pleasurable but also to recognise the pleasure and amplify it into wonder.
We can explore the limits and the possibilities of what is perhaps an accident and has no firm meaningful ground and we can revel in those possibilities: we can make things (from knitting to buildings, to vast cultural projects like science and literature), we can explore the nooks and crannies of accidental aspects of our existence ('I feel sad, actually, I feel sad enough to eat a biscuit but not to lie on the ground, weeping into the earth - OK, I'll eat a biscuit), and we can build extraordinary structures within this finite precariousness (I'm not just thinking of projects that outlive us - like medicine - but things like love and relationships with others).
There are also different degrees of whiling away the hours, and we're capable of judging and distinguishing between them.
And I do think that recognising that a lot of what we do is rounded by finitude can help in making the decisions - and better decisions - about what we choose to do. I have a personal aversion to people who seem to be very angry about death and finitude, and embark on projects that seem full of resentment against the fact of death, of those who will live after them, of those younger than them.
And, of course, there is a whole argument that one of the things men hate about women is that women have a kind of in-built connection with regeneration - some kind of 'get out' from immediate finitude - because of reproduction. Obviously, there is a whole load of stuff to unpack in there - not least the idea that that kind of regeneration is simply a deferral of the inevitable finitude - but it's an interesting idea to play with (as you while away the hours before the inevitable end).
By the way, OP, I like the way you have essentially turned Mumsnet into a new setting - like the Decameron's plague-surrounded castle, or the prison cell in 'L'Etranger' - in which to discuss these questions.