Calm down. Nobody is taking anybody down here. However...
Although it's not my first year in business, the moment when developers have an argument about UI with BAs always makes me feel uneasy. I understand that on both sides of the table there are folks who actually want to do good and there are folks who care mostly about their own opinion and/or agenda.
I am having such a discussion tomorrow. At a project where I've just started. Where nobody knows me or my (objectively good) intentions. Where the product's UI is a carbon copy of an excel sheet and nobody seems to give a damn – or better to say, the developers are worried, but BAs still have the last word (and they obviously are in love with The Excel).
I just want to hear what memorable arguments you had in your career and how you've successfully reasoned to make your point (and win it!). From "make the logo bigger" to "that white space is just sitting there - we need to use the sh*t out of it".