the word said often yet rarely from heart

This word is said often
we learn right from young age at every action to mention,
it brings a smile
it goes for mile
yet,
rarely said from heart
it's installed in our memories as at young age it is taught,
said even for small favour
and some say every hour,
and one who says from heart,
is truthful as to SAY THIS WORD YOU NEED NOT LEARN ANY ART.

children's thank you is innocent and truthful

couple being thankful to eachother

it's the small THANK YOU