Sometimes, decorators have leftover inventory from previous clients that, for whatever reason, they couldn't return to the store or warehouse. They might try to use that inventory in your space in order to get it off their books. If that red chair that you absolutely despise keeps showing up in your living room, make sure to keep an open line of communication with your decorator about it.
At the end of the day, your decorator shouldn't include things in your space that you just aren't crazy about. You're paying her to create a space that you love, not to take furnishings off of her back.