I think the main issue is the ego the R&D department thinks they know every thing and what ever they do is 100% right, so in a situation when the quality people comes and tell them according to rules you have perform this test 3000 times not 300 times to test the device then at that point they R&D start explaining theories to quality people and at that point the debate starts. I think goal of both department is same is to grow the company, but the difference is sometimes R&D is over confidence they start following their own rules and that point the quality has to step in and try to explain them that we have do everything by book. I think sometimes R&D forgets how the things can go wrong no matter how accurate and good your work is and they neglect the risk factors but the quality knows what can go wrong and how to avoid them. And that is why quality people are their to make sure that the product does not have any problems and is follows the FDA standards before it goes out in the market.