We recently bought what's commonly referred to as a McMansion. It's loaded with design features that give you the feel of something impressive, but a number of them aren't as functional as they should be. (We didn't really need or want this type of house, but when we began house hunting it quickly became obvious that the home that you "really want" isn't for sale, so all the compromises must be weighed.)
In a couple of rooms there are just too many windows, I guess because they're pretty, but they're placed too close to a corner which makes drapery placement awkward. Another thing that bugs me, from one step inside the main entrance you can see directly into the master bedroom to the left, and to the right you can see directly into a guest bath, if their doors are left opened. Oh, and that view of the guest bath is through the dining room, which has no doors from either side.
Then, of course it has a the super steep roof that is unwalkable and a huge attic that could house another family. (As a kid I'd have loved playing & exploring up there.)
Those are just some of the little things that bug me, but overall it's a beautiful home that we feel really fortunate to have. I'm sure even if we'd worked with an architect and built a home it would still have some things that ended up being a "little off".
We purchased it in 2019, so it's definitely been a great investment. No complaints about that. :)