Most often people assume these opinions have to be political, but they really don't. Well, maybe within the scope of the question as defined by OP since it exp

Most often people assume these opinions have to be political, but they really don't. Well, maybe within the scope of the question as defined by OP since it explicitly begs for controversy. But should you expand it to the broader What is an idea you hold that runs contrary to the common wisdom of field X? Then suddenly it becomes a lot more interesting and fruitful, It's not that heterodox political opinions are intrinsically less interesting but few people know how to discuss them constructively, much less online. That breeds low quality discussions where everyone is at each other's throats. Broadening the question has at least the merit of being less polarizing without giving up on critical thinking, or bravery. Ultimately, the goal is the pursuit of the truth - something that breaks mimeticism (or kickstarts it).