(originally: "Fuck you, Jack, I'm all right!!" - described the bitter dismay of sailors ("jacks") returning home after wartime in the Navy to find themselves not treated as patriots or heroes, but ignored / sneered at by a selfish, complacent, get-ahead society - phrase was subsequently toned down for acceptable general use.)
Attitude of "every man for himself, survival of the fittest, devil take the hindmost", ... but also, that all the possible advantages (however gained), success (however won) and satisfaction (whatever the cost to others) belong to me first!" Narrow-focus, narrow-gauge pseudo-Darwinian selfishness glorified as a sensible philosophy of society and life.
People who find it hard to say "I'm all right Jack!" outright, say to anyone they find no longer useful: "I'm trying to get my life in order right now, so can you respect that, please?!..." (just before they throw themselves laughing into more fun and merry chaos!)