I have a few. I'm not the kind of person that says controversial things to attract attention, but I also don't refrain from putting them out there.

A selection of the ones I use in my political activity:

• knowing things doesn't change things
• work should be abolished
• atheism and rationalism are a scourge on the ability of the Left to reach people
• hacker culture is intrinsically gnostic and reactionary

Some others:

• suicidal and self-harming people should be listened to by understanding and validating the motivations behind their desire to hurt or kill themselves, even entertaining with them their own plans. Anything else would likely put a wedge between the two of you that will prevent from addressing the causes and ultimately do what's good for them.
• mathematics is just narrative with rules/arbitrary opinions with rules
• nurses, doctors, teachers and other professions of care attract the worst psychopaths because they are put in charge of vulnerable people. On top of that they are by default perceived as caregivers, so it's harder for them to raise suspicion of doing fucked up stuff.

Edit: people down voting in a thread about controversial opinions must be very very intelligent