So yes, they kill his dog. But its not just a simple 'kill his dog - he takes revenge' plot device. Even if it had been so, that simple concept was enough to have me cheering the trailer, for a fun brainless action thriller. But no, its more. In a very truncated opening sequence, we see Wick lose his wife (silently, via disease) and gain a puppy, one she arranged to have delivered to him after her death, so John will continue to know love. This is like a reddit post, one where a guy shares a post about the puppy he is raising that his girlfriend arranged for him to have, after she died of cancer. It would gets 10s of thousands of up-votes. The feels are palpable. Its not just a shout of, "You killed my dog, now prepare to die." This is John having his mourning tool ripped from him, like his heart from his chest.
John lives in his big, fancy house
The rest of the movie is a beautiful ballet of ultra violence and gun fu, with a hint of video game. Revenge movies are a genre where you already know the direction taken (*ahem*), so you have no guesses as to plot. Any creative divergences from such are usually distracting. So, this one progresses as it should, with Wick shooting anyone who gets in his way. But oh so lovingly directed. From the locations, like the Red Circle club (a side reference to a fake-Buddhist quote about men and their destined convergences, from a movie, Le Cercle Rouge, that influenced John Woo and this movie) to the snazzy flat iron building Hotel which doesn't allow business on its premises, making it a refuge for underworld types. To the costuming; Hannibal would have felt good in these tailored dark suits. To the music, hard thumping electronic when necessary with one sequence reminding me of Blade and the opening vampire take-down. The movie just made good choices.
These movies are like candy to me. I eat them quick but the sugar high runs out. I forget much. But I know I want more and I will be watching this again, so I can catch more little things that will elicit smiles from me.