Starting with your "Balloon" series, and through this collection - Great Photos! We covered tower cranes, next is perspective distortion. It occurs as a function of lens type and camera position. It's fairly easy to correct in post. In photos of architechtural elements, verticles should be "true". Lastly come dark shadows. This is no fault of the photographer, but is endemic to photography. Cameras are set to properly expose for bright skies and buildings, but sacrifice the shadows in the process. HDR [High Dynamic Range], used both in-camera and post, with the technology constantly improving. I do it by hand using luminosity masks - another story. -Phil