Icks are a very personal thing; what one person finds unattractive could be like catnip for someone else.
It might be that he chews really loudly or that she picks her nose, or maybe the person you're dating wears Crocs, for example.
Granted, I don't think there's anyone out there who actually likes watching people pick their nose - is there? - but you get my point.
And one woman has sparked a pretty big debate after she took to social media to open up about her biggest ick'.
In a video posted to her TikTok, Jac Clark said that she was seeing a guy when she discovered something about him that she really didn't like.
He didn't go crazy about her dog.
"I think I have discovered my biggest ick," Jac starts her vid. "If you need my dog, hold on. This is my dog. If you meet my dog and you don't freak out, like if you're not, like 'Oh my God, he's so cute', and, like playing with him and giving him like a tonne of attention, what are you doing here?
"I had a man over once, and I said, 'Don't freak out, you're about to meet my dog', because he's perfect. And I came in, and Lenny was there, my dog, and he was so excited to see me and freaking out and this man just acted like my dog didn't exist. That's it. That's my biggest stick."
Seem a bit harsh? Well you're not the only one.
Since she posted the vid, it has been viewed over 1.5 million times, with thousands jumping into the comments to discuss the topic of icks.
Throwing their support behind Jac's issue, one user said: "That's not an ick, it's a dealbreaker."
Another commented: "1000 percent. If you don’t have a meltdown about how handsome and smart and perfect my dog is… yer done."
While someone else put: "He acted like your dog didn’t exist?! He’s going straight the hell home."
However, not everyone was so outraged by the guy's reaction.
Some pointed that he sort of did what she asked him to do, which was 'not freak out'.
"It's not an ick...it's actually the proper way to 'meet' a dog without causing them stress," said one.
While another added: "Wait but hear me out. You told him not to freak out so maybe he just thought that’s what you wanted?"
What do you think?