I have 2 dogs and 25 cats currently. And here are the differences I've observed:
1. When you pet them
Dog - "Ooh! I love being petted, this is perfect. I love you human. I love you so much, you are amazing."
Cat - "I wanna be petted, but I also wanna scratch your hand and watch you bleed."
2. When you feed them
Dog - “This is the yummiest food on earth, I am so grateful, did I tell you I love you human? I love you very much.”
Cat - “I don't like this food, I wanna eat that lizard on the wall or the dog’s food. But anyway I will eat this and vomit it out on the carpet. You should be grateful.”
3. When they break something
Dog - “I am so sorry human. I am never gonna do this again, I am a bad boy.”
Cat - “I am gonna knock this one off the table too and break everything to pieces, I am the God.”
4. On meeting visitors
Dog - “Oh! My human’s human. I love you too. Would you like to play in our garden? Would you like to see my bed? You can have my favorite socks. I am so excited.”
Cat - “No! Stay away. Get out of here before I burn this house down.”
5. When you call them
Dog - “I heard you calling, I got so excited and came running to you. I love you human, thanks for calling my name. I know you love me.”
Cat - “What the hell does this stupid human want from me now?”
6. When you come back home
Dog - “You've been gone forever, I missed you so much. I thought you left, I am so happy you didn't die. I love you.”
Cat - “Feed me!!”
7. Kind of presents
Dog - “I've brought these dirty socks for you. I’ve some sticks and some old newspapers too. They are all yours.”
Cat - “I kept this dead mouse on your pillow to surprise you, I’ve a bird too if you want. This is my favorite leaf, you can keep it.”
Despite all these differences both cats and dogs love their human very much!