Yeah, me too - as a designer we call it "scope creep" and it's the bane of my existence. Customers can't see what they want until something is fully designed and built, and then they change their mind on what they want, and want you to retrofit in a bandaid solution.
It's absolutely infuriating, and always results in a less-than-perfect end result.
It's absolutely infuriating, and always results in a less-than-perfect end result.