The synonyms - "Worth" and "Price"

In a beautifully decorated house, once lived a husband named Mr. Henry and his wife Mrs. Jones. Mrs. Jones was reading a letter at breakfast. While reading it, she suddenly looked up at her husband and said, “I have just received a letter from my mother, saying that she isn't accepting the invitation to come and stay with us, as we are not willing to invite her. What does she mean by that? We never told her this. We have always been very eager to have her at our house".
She was lost in thoughts. Immediately she asked her husband (as a confirmation), if he had written that she was to come at her own convenience. 
Mr. Henry faltered a bit, and said “err, yes, I did”.
After a while, he said, “Actually, I couldn't spell the word “convenience” so instead I wrote “risk”. 

I presume, you can now make out the whole meaning of the letter which said she had to come at her own risk.
A little twist in words changed the meaning completely. Right.

In English, the words "Worth" and "Price" are synonyms but adding the suffix “less” makes their meaning poles apart.

Worthless means good for nothing and Priceless means invaluable and so precious that its value cannot be determined.

You know, Guru sahib uses both these words in the same sentence. Do you want to know how?
He says, " The life we have is priceless because it isn't found again and again, yet, we are wasting it by engaging in worthless tasks that aren't going to help us grow.