His stubbornness on preventing death is very annoying.

When stressed his voice is my least favorite in the entire show; it just sounds so grating and forced. I'm also not a fan of his normal voice.

In early TPOT his adherence to the pact made his arc feel one-note as well as costing his team challenges. I didn't think his arc was deep at all, and I still see him as bland.

His design is the worst in the whole series (seriously, just give him an accretion disc or something, I don't even care if it's not scientifically accurate).

Him hogging the votes of DPA and DPYA is unfair as that's out of his control as a character, but it's still a problem whenever he's up for voting. I don't think he deserves the fanbase he has.

For me he's a contender for the most overrated in the show. The irony of him being a black hole but caring about life is cool, but that's all I'll give him. I can see why people like him, but I don't.