I find the biggest distraction with many HDR photos is extreme increase in detail and extreme sharpness in every part ot the photo. Sometimes it's startling and disquieting.
It's like the difference between filmed movies and videotaped TV shows - though improvements in video are making them almost indestinguishable.
Let's remember that the human eye is only in focus within about a 5% cone in the center of vision - everything else is blurry. We are also only able to focus at a certain distance - objects closer or farther are blurry. Our brains do a miraclulous job of interpreting these tiny areas of focus with subsequent glances to different parts of the scene to create what we perceive to be a landscape with everything in focus. But subconsciously we recognize that a real 3-D landscape requires certain eye movements and compensation to process properly.
When we look at an HDR photo - especially one where objects are relatively close (like the garden/gazebo shot), the equal sharpness of all items in view doesn't feel right - it doesn't feel real - it makes us subtly uncomfortable.