You're born with a ton of fucks to give, so you spend them like a kid with a credit card. You give fucks about your friends, about your grades, about your fashion sense, about strangers' opinions. You give way too many fucks about way too many things, you
have so many. Then, as you get older, you have maybe 10 fucks per month, so you learn to budget them. You allocate fucks to family and career, but there aren't enough fucks left to give to the newest fads. Oh, someone at work has something they need my help with that's outside my job title? I'll do my best to allocate some fucks, but this month is pretty tight. Then, as you get even older, you're down to 1-2 fucks a month, and those fucks are damn precious. You give them to your family and your hobbies and your job, and that's kinda it. It's not your fault - fucks expire too quickly, I would've liked to save my fucks from when I was younger but I can't. Then, you hit fuck insolvency. You're getting like 1 fuck a year, and you have to make it last. So you go without, and even previously fuck-worthy things, you just can't give a fuck. Some people run out really quickly, some people have a fuck trust fund that pays out a decent amount even into old age. But at some point, the fuck faucet runs completely dry and you're out of fucks to give. It's just basic fuckonomics.