Lobster is usually on the menu if there's a celebration or a special occasion, but that wasn't always the case. Lobster used to be regarded as an embarrassingly commonplace food; in fact, it was so ubiquitous on the East Coast that people were only allowed to serve lobster to indentured servants no more than three times per week.
Prisoners in colonial America regularly ate lobster because it was regarded as a "trash food." The colonists believed that anything that could just wash up on the beach (droves of lobsters did then) wasn't worth eating. It was also common to cook lobster when it was already dead, which may have made the taste less appealing. Early Americans continued to eat lobster primarily because it was cheap, though eventually they preferred the canned variety since it made what they were eating less obvious.
So when did people stop feeding lobster to cats and start viewing it as a delicious delicacy? When the railway system began to stretch across America, people were served lobster on trains. Those who didn't live on the coast didn't know it was supposedly a worthless product and happily ate the new, enticing food, which drove up demand and the lobster's popularity.