What do 開眉粥 and 愁眉飯 mean?

To put it simply, The rice is more resistant to hunger than congee. In Cantonese, "eating rice or congee" is often used to describe the outcome of a thing. "开眉" means "happy" and "愁眉" means "unhappy". So this sentence can be interpreted as: Do you want to be happy to do what you want to do, or unhappy to do what you don't want to do?

開眉 implies 眉開眼笑 (happy expression)

愁眉 implies 愁眉苦臉 (sad expression)

One cup of raw rice can only make two bowls of cooked rice (飯)

One cup of raw rice can make up to eight bowls of congee (粥)

粥 is watered-down 飯

Poor families often only have enough raw rice to make congee for every member to have a full bowl of staple food

"寧吃開眉粥，不吃愁眉飯" literally means "rather eat congee with a smiling face than eat cooked rice with a frowning face". It is a metaphor for "Better live a poor but happy life than a rich but unhappy one"

(diminish the importance of material wealth)

You can use this expression to describe a situation like someone rather take a low paying job than earning money with immoral acts

Side note:

Cantonese expression: 有粥食粥，有飯食飯 = through thick and thin