It doesn't earn you money.

Once spent, that is it, money gone.

Imagine you've saved up 1 year worth of savings and then you spend on a 2 weeks "Arctic Odyssey" vacation which cost about RM50k.

1 year worth of blood sweat and tears gone in just 2 weeks of adventure.

Of course it doesn't feel that way if you are filthy rich or doing it when you are already retired with more than enough money till you know you can't bring to your grave.