How often do you correct the perspective of your picture via post processing? All lenses, especially those wide angle one, will exhibit a certain amount of distortion. Besides that, when you are not careful when framing, it’s easy to have slanted horizon or vertical lines.
For landscape shots, I think generally with levelled horizon it is more pleasing and… natural to viewers’ eyes. For architectural shots, it really depends on the framing itself. Sometimes I will do a perspective correction to ensure buildings are levelled, sometimes I’ll go a step further to ensure even the vertical lines do not converged.
Slightly slanted shot, before and after levelled.
For streets shots… Well, I think there should be more freedom for this type of shots. When Adobe first introduced the auto perspective correction in Lightroom, I tend to abused it by clicking on the auto adjust on every single image that I shot, even for street shots. Until one day, I realized that… hey, why everything seems to be so… formal and boring. There onwards, I started to put in more thoughts into my picture before clicking on the adjustment button.
Levelled street shots are okay, or I would say they are pretty “safe” in terms of overall composition. Some shots when slightly slanted just give you more energy into the picture, letting you to feel closer to the action. Well, it may not be something that’s to everyone’s liking, but that’s where the fun and creativity of photography takes its place. Take your imagination to fly, step out of the box, and enjoy shooting folks 🙂