you know the things you think you have to do then after you think why on earth did i bother?
many a time i have spent hours carefully putting the stickers on toys bikes etc to complete it then two minutes after kids open it all the stickers are ripped off!
you risk life and limb not to mention driving miles to get that toy that your youngster has begged for along with most of the kids in the UK but on Christmas day its played with for 2 minutes then discarded never to be seen again
similar to above you have that one guest you want to impress/who is awkward so you spend ages finding food you know they like at great expense then find out when they visit they no longer like it!