I have taken (and given) many, many editing tests in my life, and one thing has become very clear to me: I will never be able to spell poinsettia.
It looks wrong to me no matter how I spell it. First, it seems like it ought to have another T in there somewhere. Pointsettia? Then I realize that, no, that’s absurd. Oh, wait, I know: The -ia at the end is all wrong. Needs to just be an -a because that’s how it’s pronounced. I think. Look, I’m not a florist.
Poinsetta. No, still looks wrong.
Luckily, most programs have dynamic spellcheck by now, and lucky, too, that there is just not that much content that contains this cursed plant.
I also look up siege and seize every time, too.