For me, 10 tbh. Shu is a big sweetheart in his route, so when I chose all the bad choices just to complete the achievements, I felt that I'm the worst person in the world.
If you really don't want the pain and don't mind skipping the heartbreaking story, you can change the setting of skip by checking the unread text, so you can just skip it. But you will still see his hurt, disappointed and angry expressions, and the most heartbreaking CG of all imo.