The short answer is no, and here's why that's a good thing
Some builders are what one might call 'order takers.' They do anything the homeowners want (sometimes) within the constraints of budget, timetable, and zoning or code regulations. That's understandable; everyone wants happy customers and positive reviews.
But the best builders understand that an anything-you-want approach really doesn't serve customers. We would go further and caution people to beware the builder who never pushes back.
Don't misunderstand—all custom builders try hard to accommodate requests. After all, they are building custom homes. At the same time, they also know that protecting customers may mean vetoing certain requests.
A good way to illustrate this is with the examples of mechanical specifications and/or special building materials. Just because a co-worker or friend read an article online or saw something on HGTV doesn't mean it's right for your home. More HVAC tonnage isn't always better. A special type of house wrap or exterior sheathing may not be right for your climate or regional conditions. A good custom builder will take the time to educate their clients on why they're specifying the products and materials used in your home.
While the client's opinion is important, long-term satisfaction depends more on performance than on price or other factors. It's the builder's responsibility to help the homeowner understand that.
The builder's HVAC contractor will calculate the optimal system needed to keep the home comfortable and healthy. The builder may then recommend a more expensive system or may limit choices to one or two very reliable brands.
Recommending the higher-priced product isn't a sly attempt to jack up profits. It's a sign that the builder is looking out for the customer's well-being.
Builders with a reputation for durable, high-quality homes earn that reputation because everything they do supports it. Using cheap products that fall short of the builder's performance standards would be like putting Hyundai parts in a Porsche. That's no criticism of Hyundai; it's a recognition that builders, like car manufacturers, have to deliver on their brand promises.
These are only a couple examples. Many homeowners also request specific windows, deck boards, interior paints and other products. A builder's willingness to use them depends on whether they meet the builder's standards. That's a good thing for the homeowner.
Builders with great reputations put a high priority on good customer relationships. Good relationships are based on trust, and one earns trust by telling the truth.
But trustworthy builders don't leave customers disappointed. Instead, they suggest products and designs that offer the benefits customers really want from their new home.