Dog.
I grew up with a cat in the house and then got a cat of my own when I was in my early twenties. I had never bonded with a dog. My cat died young. Sad.
When my wife and I moved in together, her dog came along obviously. I bonded with it quickly and started to understand why they call dogs man's best friend but I still wasn't sure which animal I liked more. Fast forward about 3 years and we decide to get a cat. He's cool enough but I realized how poorly I can communicate with the cat and how well with the dog. Also, the dog appears to care about my wife and I vs. by how much the cat cares by orders of magnitude.
It took me getting a cat after only having a dog for a while to realize dog >> cat.
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