I guess it depends on the feast!
Some are celebratory (think Easter, Christmas, or Saints days), others are more solemn (think Good Friday), etc…
“Feast” in this term, really refers to the “feast” of the Mass… the celebration of the Eucharist. We are called to celebrate the Eucharist on Holy Days of Obligation… sometimes referred to as “feast days”… other feast days - like for saints - we are reminded of those who have gone before us in faith and we celebrate their lives… either by attending Mass or having a private celebration at home.
This is a great article on feast/holy days, in general…
newadvent.org/cathen/06021b.htm
My personal experience… obviously the “big” ones are BIG… Christmas, Easter, etc… but some of the other Saints Days are celebrated more quietly. I think the only one we actually have a “family meal” is on St. Patrick’s Day, which is a huge tradition in my family to have corned beef, cabbage, and potatoes (yes, I know this isn’t traditional in Ireland… I don’t live in Ireland

)… and to dye everything green - including the milk.