At my last duty station there was not a lot to do out in town, so me and a few people in my training group ended up putting a lot of hours into volunteering at a dog shelter nearby (because it was a good thing to do, but also because it looks good on an evaluation 
). We would mostly walk them and give them social time outside their kennels.
My first reaction was feeling a lot of empathy for the dogs, seeing their little kennels and their “yard time” and overall prison-like existence - and comparing that to the lower-enlisted housing that me and my shipmates were confined to at the time (tiny! So tiny!! We were living in closets!) and our demanding training schedules… It was easy to consider the dogs our fellows! The shelter for a lot of us was a good reason to escape the military environment and spend some time outdoors, so we were essentially getting the exact same benefits as the dogs 
I’m not much of a dog person though, and even if you are one you can admit that they can be messy, chaotic creatures at times. Over time, even walking in each day with the attitude of “I’m here to serve these creatures”, I’m not proud to admit there were things would put miles on my heart and wear at my good will… The dogs you encounter working at a shelter, as you can imagine, can vary greatly - from the sweetest gentlest empathetic little darling to the hyper-dominant energetic alpha type that drags you around on the leash during walks (I can still feel my shoulder joints aching!). And then there was the deafening cacophony of competing barking that would start up as volunteers began to arrive - as you would walk past each kennel to get to your dog of choice (we would always choose based off of time since last walk), even with ear protection you could feel the power of some of the more aggressive dogs’ barking vibrate through your body, smell and feel their hot breath and get hit with flying bits of spit, slobber, and I don’t even want to describe what else.
And in the chaos of getting a dog in or out of that environment, you could never predict how any one of them would react. After securing the leash and opening their pen, most would just wildly scamper toward the door full of adrenaline. Others would do all sorts of wild, better-left-undescribed things… but needless to say it was a lot for a cat/ bird person to stomach, and I found myself regarding some specific dogs with a certain amount of disgust. But even still, I would never avoid giving walks to any specific dog.
Near the end of my time there, I made a connection - in the same way that these dogs are shown grace irrespective of their temperament and behavior, grace does not discriminate with us either. There is no karma that disqualifies someone from receiving love from the divine, in whatever form it comes! As a thought experiment I would imagine God looking at sinful people the way I would look at some of the ‘unsavory’ dogs: perhaps with a little distaste but full of compassion and understanding. It’s a beautiful simile that I still think back to whenever I find myself slipping into judgement. ALL dogs go to heaven!
(Excuse the Judeo-Christian terminology, that was my main operating system at the time!)
But on a less heavy level, spending time helping animals will quickly fill your heart - I never volunteered much at shelters before that so that was a nice little discovery process for me. If you don’t receive a lot of external gratitude during your week, go walk a couple dogs!
