I'm surprised that know one has mentioned Easter Eggs. It seems to be that the same philosophy would apply. There are those who, upon finding out there are Easter Eggs attempt to find every one in the game. The difference being achievements are listed.
A more annoying difference is that "Achievements" are blatantly thrust in your face with a flashing announcement covering up part of the screen and reminding you in no uncertain terms that you're ONLY
playing a game. Say goodbye to suspension of disbelief.
Easter eggs are generally much more subtle. At least they always used to be, and it was pretty special when you found one. Not like getting an "achievement" simply for having reached a certain point in the game or having collected a certain number of unnecessary items of the same kind.
The option to play a game without the achievements flashing in your face or showing themselves in any other way would be a bonus.