To expand on my previous answer - most companies have an "avoid" list. If you put somone on your list, the software does it's best to avoid putting the two of you together.
I've only ever put two people on my avoid list - one for constant, wildly inappropriate discussion, even after I asked him to stop. The other was just a holier-than-thou, god's gift to aviation guy I couldn't stand.
The flight attendants have a similar list - I was once in a cab with the other pilot, and two FAs - the one FA was telling the other FA how they had almost 60 people on their avoid list. The captain was sitting in the front seat, reading the newspaper. He casually lowered the paper, leaned back, and said "Did you ever think it wasn't everyone else?", and goes back to reading his paper. LOL