Examples:

• Those two children always fight like cat and dog.
• Those two always fight like cat and dog, I don't know how they're still married.
• She and her sister fought like cat and dog growing up, but now they're the best of friends.
• He and his brother-in-law fight like cat and dog, I can't stand being in the same room as them.
• They're always fighting like cat and dog, it's no wonder they're getting divorced.
• I can't believe they're still friends, they always fight like cat and dog.
• She and her coworker fight like cat and dog, it's so uncomfortable to be in the office when they're both there.
• His parents fight like cat and dog, I don't know how he grew up in that environment.
• They're always fighting like cat and dog, I don't know how they're going to run this business together.
• His roommates fight like cat and dog, I don't know how they're going to make it through the semester.
• She and her step-mother fight like cat and dog, it's so hard to be around them during family gatherings.
• I can't believe they're still together, they fight like cat and dog all the time.
• His kids fight like cat and dog, it's impossible to get them to agree on anything.
• They fight like cat and dog, I don't know how they're going to survive living in such a small apartment.
• They're always fighting like cat and dog, it's no wonder they're not making any progress on the project.
• His friends fight like cat and dog, I don't know how they're able to hang out together.