We've had our floating shelves in our living room, for well, it seems forever. Maybe 10 years or more, absolutely nothing wrong with them, but I felt like they're slightly dated.
This was how they looked. Like I say, nothing really wrong, I just felt they looked harsh.
Simon, took them off the wall, and down to his workshop, where he fitted architrave around the outside edges, with wood glue and nails. 
I then got to work with the paint, and voila.
All done, and back in place.