1. Our client appreciated all the work we did for him.

Stative Verbs - List of Stative Verbs & Exercises | Ginger
How do I understand that "appreciated" is a stative verbs and not an action verb.
I know I have asked this question multiple times but I don't know the actual meaning of "state" and "condition" in the grammar context.
I know the rules that they don't take " ing" and there are different types of state verbs.
How do I know and explain to my 6 year old that "appreciate" is not a physical action like run, cry, smile etc.? I find the meaning of "state" or "condition" bit difficult and confusing.

JigneshbharatiI know I have asked this question multiple times

If it helps, most native English speakers do not, as they speak or write, have any conscious idea of the distinction between stative verbs and dynamic verbs. Most speakers would probably not even be aware of those terms, or understand what they mean. If you asked an average speaker why e.g. "He is owning three cars" is incorrect, they wouldn't formulate the answer in those terms. They would just think "We don't say that".