If you want to show people how much you appreciate them, don't say thanks.
Don't tell them that you appreciate them.
Show them.

The person you are now is not the person you were yesterday.
The people, places, and things you interacted with days past shaped who you are now.
How did those people, places, and things shape you? What did they show you?
How did they challenge you?

Appreciate people better by showing them how they challenged you to be a better person today.

What we want to see is that we can make a difference.
A way to see that is through someone else showing us what we did.