If you are interested at all in being a great Christian, you have either asked the question yourself or heard the disparity between the Catholic and Protestant answers to "How are we saved?". I have friends that I will thank for something and they, knowing the goodness of God being truly the cause of every goodness, redirect (as it were) the thanks to God. "How are these related" you may wonder. Welcome to the subject of the post. It has everything to do with whether there is much wisdom in this action or if there remains the tiniest error. Every thank you from one finite, contingent good to the next, is never truly to fall upon the finite, contingent good, but include all the good transmitted to and through them. This is to say: an act of gratitude is applied to its source which is finally praise of God but also in the measure the finite, contingent being/good willed freely whatever is praised, the gratitude is analogically applied to them and analogically all that gave rise to them and their ability/inspiration to will the object of the gratitude, which is perfectly the case in God. A Thank you thus touch every finite good through which other goods came until it finally comes to rest on Goodness Itself, the other of the good that is man, and therefore the good that comes through him, and all this is known through answering the question of how we are saved.
Let us concern ourselves first with the question of salvation and then we shall refer back to the nature of a thank you after. If we believe that we are to be saved, we must believe there is a means to that end. But, what, if any, role do we play in that? Let us consider love. Love is willing the good of the other, but there it is "will". Does love have any value if not chosen freely? It seems the only acceptable answer seems to be that without being freely willed it cannot have much for final value. How would it be that Love Itself does not create that which is truly free to love? How would it be that Goodness Itself does not create goodness? Ah and so we are, and less so in our sin, good, but always shall be made for love i.e. loving and being loved. There are two things that compel us to do so the simple fact of being made for it and God's grace which ordains it. Are we any less free, no but greatly helped indeed. Moreover, it is not as though we are spared the influence of the enemy, which certainly always remains an option. For the virtuous, as unthinkable as it might become, the path of destruction always begins in the smallest things and so in the smallest things love must be. For the sinful, the path of destruction is well provided for by the enemy in every illusion just as a cuttlefish waiting to consume its prey is the enemy. Many, in fact, lament the freedom they have to sin, because they so wish to choose good rightly and yet stumble. Struggle does not mean for a lack of freedom though. As the Church Father Tertullian has said, "God did not will to save us without us". In joining humanity to Himself, the Master suffered and saved that humanity, so then humanity joined to Him by ways He bestowed in sacrament shall also suffer and love complete the redemption and bringing life. Undoing what was lost in disobedience through obedience, in clinging to God undoing what failure in that had wrought. Just as love binds not by a single force but two mutual forces so also it takes both God and each man to accomplish that salvation. It is not as though we are unhelped that it all depends on us nor are we forced, but drawn as a lover to the beloved and helped beyond imagination in our weakness both by Divine grace and mercy without which salvation is not possible. It takes all of God and all of us!
In conclusion, what is a thank you? It is analogically oriented toward the creature addressed and primarily and analogically meant for the Creator. Is saying thank you to a creature to say there is not another One more worthy of praise? No. Is giving thanks to the Creator to forget of the creature, even should He be most responsible? Not so. It is not correct to forget the creature or the Creator when expressing gratitude. It is unwise to try to explain emphasizing one side or the other of thanks, only be willing to bestow thanks upon whom it is deserved however much it is deserved. Hence is the connection between giving thanks and how we are saved. It lies simply in how good rent i.e. the Kingdom is brought about. Love is done by both God (perfectly and infinitely) and man (willed and provided for by God even if weakly, corruptly, and finitely on the part of man). May we remain free to love and accept the grace where it may be found to love and remain free from the grip of the enemy upon our faculties. Always may we be grateful to the God who made it all so, and regretful of man when he forsakes what is Holy.
Written by Carter Carruthers & also available at Vivat Agnus Dei
Psalm 111
I will give thanks to the Lord with my whole heart,
  in the company of the upright, in the congregation.
Great are the works of the Lord,
  studied by all who delight in them.