Why is the Source engine so comfy?
>>745991681the human mind craves photographic textures on simple geometry
Lots of straight lines and surfaces, with evocative texture and lighting work. There are several different aesthetics which innately appeal to people when done right, and one of them is industrial/urban settings. Note how the environments are quite visually clean and easy for the eye to follow, as opposed to trash-ridden alleys or chaotic looking city scenes you typically get when hacks try to create urban settings.