Clients are happiest when work goes quickly and smoothly. Quality is highest and cost is lowest when work goes quickly and smoothly. There's really no downside.
However, homes that are built quickly and smoothly tend to have a significant amount of planning done before any construction begins. There are two main approaches to building a home—the ready, fire, aim approach and the measure twice, cut once approach. While it may seem counter-intuitive in terms of time, the latter approach that requires more planning tends to result in a quicker and smoother build.
Many builders employ a "Ready? Fire! Aim!" method of building. They will draw a set of plans, make a few notes, and give the plans to the contractors who will execute those plans. The builder will solve problems as they arise, including reworking problem areas as necessary. They may make excuses and blame the contractors for poor work or lack of planning.
Here's how it might work out in your home build.
The framer didn't get clear instructions on the roof structure, so he built it however he wanted to. But that meant that the heat and air contractor didn't have anywhere to run his duct work. So the heat and air contractor called the builder, who called the framer, and the framer found a solution. He reframed some of the work he'd already done.
Then, the builder called the heat and air contractor to come back out, but he was already on another job, so he wouldn't be able to come out for a week. The builder sent the framer payment for the rework (paying him twice for the same work, essentially) and the job has fallen another week behind schedule.
Unfortunately, preventable setbacks like this happen too often during custom home builds. You may have even heard horror stories from friends or family that sound a lot like this one.
The other approach to building requires much more planning on the front end. These builders will draw up a set of plans and review them with the client to make sure the plans meet their needs. They will modify the plans as needed until the client is happy. Then, they'll review the plans with all the contractors to get their input and plan each phase of construction to ensure there's no rework needed.
Then they'll review the schedule with all the contractors and make sure each contractor has all the information they need about the job: plans, specifications, color selections, schedule, material availability, job location and driving directions, and the point of contact for the project.
Only after they have done all that prep work will they start building your home. Any problems that come up at this point will be minor.
When you're deciding which builder to use to build your home, ask your builder how they prepare for a building project. If their answer makes you nervous, you may want to talk to a different builder.