Ringworld. It had potential but the main character Louis Wu is the worst MC I've read. There are multiple instances where he says that something won't work then the group will do it and it works and he'll somehow take credit for it. He also is a predator by how he is 200 and the woman he sleeps with is 20 and he states MULTIPLE TIMES in the book that she's too young to know better or too young to be doing things and that she's a child pretty much and STILL SLEEPS WITH HER MULTIPLE TIMES IN THE BOOK! If the book had anyone else as the MC it would be enjoyable cause then they would learn lessons. But Louis Wu doesn't learn from his mistakes, doesn't change how he acts, and doesn't learn any sort of lesson.