“….May the Lord make us truly thankful” at the end of a Grace before a meal always seems to imply that I will not be thankful on my own. This could be to do with the cooking, or it could be about me/us. The sermon looks at two stores where thanksgiving was real, spontaneous and joyful.
It would be nice to have that spirit in us too. There is a way that you can practice to have that spirit of gratitude grow and settle into yourself. it is outlined in the last section.
I hope this helps