expressions - Person who pretends to not understand unless one speaks in exactly the words they expect

There's a scene in the movie, "2010," that comes to mind.

An astronaut and a cosmonaut are enduring a challenging experience. The cosmonaut says, "Easy as cake!"

The astronaut corrects the cosmonaut, replying, "Pie! Easy as pie!"

Later, the cosmonaut says, "Piece of pie."

Again, the astronaut responds with, "Cake! Piece of cake!"

We weren't given examples of what the OP said that his colleagues corrected. We were told that English is not the OP's native language. English has idioms that are difficult for non-native speakers to grasp. What do cake and pie have to do with a task's level of difficulty, anyway? Still, the majority of responses jumped to the conclusion that the native speakers were probably just being jerks, so sure, go right ahead and cast aspersions - we'll even show you how.

I suggest that the OP take help where he can get it. The OP, however, should not forget to Доверяй, но проверяй.