The source of the problem most likely has to do with the similar pronunciations of great and grate.
The thing is, grateful has no link to ‘greatness’, but rather to ‘gratitude’. When one is grateful, they are thankful and appreciative, usually for something or to someone.
I am grateful to be in good health.
I am grateful to my colleagues for all their help.
As I was writing this blog, I wondered about how the Grateful Dead chose their band name, so I looked it up.
Wow. A few stories popped up, which made me smile, but the consistent version is that Jerry Garcia got the band name from a dictionary he randomly opened one night, and thought it was the most stunning combination of words.
Sounds like more than reading from dictionaries happened that night. ;)