He who is grateful gets to experience more in abundance as it is in the nature of man to feel appreciated, we may act all humble and nonchalant in these things but deep down within every man is the inherent need to be appreciated for the good they do. This is why those who show gratitude get to go higher.
Even in the Bible we come to realize that God himself appreciates gratitude not as if our thanks would do him anything but he does appreciate our thanks and it motivates him to do even more for us in that regard, similar thing was seen when Christ questioned the lepers who came back as to the whereabouts of the others.
Showing gratitude is not a difficult thing to do and it is an easy habit to inculcate, you only need to practice once, then twice and you will get it to be a part of you, for it to flow through your bloodstream, If you have ever had the opportunity the to experience someone showing gratitude to you for something you may have done to benefit them you would come to understand what i am talking about even more.
Gratitude will take you places and it is the best form of humility there is in man, he who learns this act has learned a great deal and its meant to succeed in life because lots of goodness will come your way and people will be drawn to you because they would love to help you whenever and wherever they can. I do hope that we all learn to show gratitude.