10. The Low Amount Of VFX Shots
It's no secret that Nolan prefers practical effects over CGI. Inception, for all the surreal imagery it presents, still used practical effects over computer-generated when possible.
Generally, movies heavy on visual effects have upwards of two thousand visual effects shots. Inception only has about 500.
Things like the Penrose stairs, the rotating hallway, the mountain avalanche, and zero-gravity sequences were actually created through practical effects. No CGI was used for those at all.
Of course, not everything could be done practically. The scene where the city bends, for example, could only be done with CGI, though they made it look as convincing as possible. CGI effects like these are sparse throughout the film.