I find this comparison really interesting. In my opinion, the left lane slow drivers are like the people who save tables. They "save" their spot in the left lane so that when they eventually would need to pass someone going slower in the middle or right lane, they don't have to try to switch lanes which may be packed with other drivers. They find it easier to stay in the left lane than to risk not being able to switch lanes when they need to. They disregard the fact that if less people drove slowly in the left lane, it wouldn't be as difficult to get into the left lane to pass somebody as it wouldn't be as gummed up with people who didn't need the faster lane. They don't see how them driving slowly in the left lane is inconsiderate to those in the other lanes who can't get around them.
Likewise, people who save tables save their spot so that when they eventually do get their food, they don't have to worry about looking for and finding a table. They find it easier to already have a table than to risk not being able to get one when they have their food and need it. They disregard the fact that if less people saved tables, it wouldn't be as difficult to find a table once you had your food as the tables wouldn't be so crowded with people who didn't need them. They don't see how saving a table is inconsiderate to those who have their food and need a table but can't get one.