Many people experience the same memory together, but often remember the memory differently. There are many things that make this true. Such as, if two people go to the zoo, they may remember it completely differently. If person number 1 liked the lions and person number 2 likes the monkeys, they will remember their emotions differently about the animals they were around.
Explanation: In this context the apostrophe show ownership, or WHOSE waters became choppy (I know an ocean is a WHAT and not a WHO but phrasing it like this in my mind always helped me). Without the apostrophe it would be the plural form of OCEAN.