We teach Junior to say thank you when he is young because you want him to be polite and maybe learn to be grateful.  We find that true gratitude to God must come from a heart that the Holy Spirit has worked.  In this passage we are told to put on some godly characteristics that cannot be accomplished in our own power, but must be done as the Spirit accomplishes it.  These godly characteristics along with peace and gratitude cannot be accomplished by artificial means or determination, but can only be done by the Spirit working in the receptive heart.