If you are referring to a singular possessive noun, it should be consumer's interest(eg.), but if you are referring to a plural noun it must be consumers' interest. If you are saying it's your style, you don't have the right to speak about grammar. It's my style!
There are thousands of language can be spoken in their own style. With an international language you cannot use your rule and style globally, but you can use it at home YOUR STYLE.