As an example: "weerhouden" in Flemish means "to be included", while in Netherlands' Dutch it means "to be excluded".

Or take "poepen" which means "to have sex" or "to take a shit" depending on which country you are in.

I frequently have to ask my friends from the Netherlands to clarify something because, even though I hear which word they're using, I have no idea what they mean because the words mean something different or are just never used that way in Flemish.