Proverbs 23:7 in the King James: "as a man thinketh in his heart, so is he."
In newer translations, the word change is pretty great:
"he is like one who is inwardly calculating...(he says one thing)but his heart is not with you." ESV
While the words are quite different, the message is the same...in dealing with others, and dealing with yourself, it is the interior message that is the big one, the one to watch out for. A person can say one thing, but be thinking another. The message: be very careful about the inner words. What are we saying/feeling/owning inside?
I may be saying, "nice to see you" but be actually feeling annoyance at the interruption.
I may be feeling a bit irritated that I am not getting my way, while acting "just fine."
I may be smiling, while feeling pushed into some new practice, or territory.
Recently I have been self-talking in situations like this.
Saying within: "this is not that big a deal, relax"
Or: "this is going to be a good thing, be a part, enter in"
Or: "it's not that much money, and it will be cool, enjoy"
It is amazing what a bit of inner dialog, heading in the right way, can do to change the old, often selfish habits of the heart.
So join me, mutter some good stuff...and grow in Christian grace.