It’s not that they are trying to annoy you, well, it’s probably that too, but a recent study reported in Discovery News shows that wolves, and by extension their doggie descendants
In other words they choose where the pile will be seen the clearest and smelled the strongest. It might be the middle of the sidewalk or on a neighbor’s pristine lawn, rather than in the underbrush or gutter.
For dogs, elimination is not just a need to relieve themselves. It’s a way of communicating with other dogs. Doggie doodoo can inform other dogs of their identity, mating status, control of territory, and probably some other things people don’t know about.
In a city, fire hydrants are large and open on all sides. If a dog relieves himself there, the scent lingers and other dogs can smell the pee-mail thirty feet away.
If you’ve ever walked a male dog, especially a small one, you have probably seen him trying to pee as high as he can on hydrants, trees and fences to leave the message that he is larger than he really is.
We are certain that Timmy our stud muffin must have fallen over backward several times before he perfected his present impressive small-dog-on-the-brink-of falling-over-backward stance. Following an ingrained instinct, he is marking his territory as his ancestor, the wolf, does.
On the other hand, it may be that dogs simply use their need for elimination to annoy their owners as much as possible.