I'm a massive animal lover, all animals. First and foremost, cats. But I absolutely adored my dog, whom I lost last year when he was fourteen. Miss him every day and would love to have him with me again.
However, I put a lot of effort into training him when he was a pup. Both me and the dog absolutely loved our training sessions! Dogs are born to please their owners and if done properly, they get so much mental stimulation from training. My dog was trained to hand signals and could reliably be walked off lead along a very busy road. But did I walk him off lead? NO! Because I would never forgive myself if my training failed and he ran into traffic.
He absolutely LOVED people. He was ambivalent about other dogs, due to being attacked twice at a dog park when he was just a littlie. He was never aggressive towards other dogs, just nervous when they came to "say hello". I used to hate it when off lead dogs would come barreling up to him, their owners giving the usual "Don't worry, he's friendly!" cry. Yes, your dog might be friendly, but my dog might lash out at your dog because he's scared and then it would all be MY fault.
I don't think any owner should ever fully trust their dog. I certainly never did. Dogs are animals and they will defend and protect themselves if they feel they are under attack. And never, ever trust a dog around children! Kids have a habit of getting in your face, staring directly into your eyes, not picking up on warning signs, etc. These behaviours are all triggers to dogs - staring directly into a dog's eyes and forcing them to stare back is a direct challenge and the dog will respond accordingly if it feels threatened.
Learning about animal behaviour is a passion of mine and it should be for all animal owners. How else are you going to learn what your pet's behaviour means? How else are you going to learn whether it's your own behaviour that's creating bad behaviour in your pet? I honestly believe that pet ownership should only be available to those who have gone through some mandatory education and have been proven to be able to provide for all their pet's needs, both financially and emotionally. There are far too many mistreated animals in this world, far too many dumped and forgotten animals - it breaks my heart and it's got to stop.
Lastly, the anthromorphism of pets also has to stop. They are animals, first and formost and you cannot attribute human characteristics to them. It is detrimental to an animal to expect human behaviour from them. Please don't dress them up (unless it's a coat for warmth), take them to human venues and expect them to behave like humans. They can't. They're animals. They are totally dependent on us for their needs and for us to expect behaviour from them that isn't within their capabilities is nothing short of cruel.
I guess the TL;DR version of this is you, the owner, are the one who's entirely responsible for your pet's behaviour and wellbeing. Pet ownership is a privilege and is for the life of the pet. If you can't commit to doing the right thing by your pet ALWAYS, please don't have one.