They may wag their tails to express excitement, affection, love which is in a way their way of saying 'thank you'. Here are other ways a dog shows gratitude to humans as explained by an expert.

These other ways to say thank you express a bit more meaning, making your expression of gratitude much more impactful. Please accept my deepest gratitude. I'm forever in your debt.

15 Super Cute Ways to Spoil Your Dog Happy National Spoil Your Dog Day! Yes, it's an actual holiday. By Emily Spain Aug 10, ... your pup will thank you for making the switch. $55.

12 Ways Your Dog Is Trying to Say “I Love You ... but when you think of it as an endearing sign that your dog loves you, it’s kind of cute. ... thank you very much!