Sometimes building contractors make mistakes. They built the walls in a friend's bathroom too close to the waste stack pipe in the floor. As a result, when the toilet was seated by the plumbing contractors, it turned out to be too close to one of the side walls. It was uncomfortably tight. They lived with it for years but now they're remodeling the bathroom and wonder if it would be a significant plumbing repair to fix the toilet.
I told them about the offset toilet flange, which can have the effect of correcting a builder's mistake by allowing the toilet to be moved over a few inches without having to move the waste stack pipe in his concrete foundation, which would be among the more expensive bathroom plumbing solutions.
The offset flange is a great invention. I've heard from a few plumbers who think the offset angle restricts water flow and results in a less powerful flush, but even if that were true, there are more powerful flush valves that will help overcome such concerns. I think the offset is a toilet fix breakthrough. I wish I'd thought of it.