yea, Ryan, the main character, isn't in a happy place at the start of the show. we learn a lot about him later on, such as he was a lawyer for his dad's firm and he did some drastic things to win cases, which we find out near the end of the first season. the show is basically "What is Wilfred?" because everyone else sees him as a dog, but Ryan sees him as a guy in a suit. And there's more to it than that even, but I can't go into that because I don't wanna spoil too much. Just know that to everyone who isn't Ryan, Wilfred is just a dog. To Ryan... well, we really don't know what he is. Why he's here, why only Ryan sees him, etc.
it's weird and can be dark at times, but other times it's one of the funniest shows i've seen. the dark humor and dark aspects in general are fun as hell