eucharisteo!

Eucharisteo...the practice of giving thanks. I have recently realized that the one thing my children do that frustrates me the most is verbalize their ingratitude (or show it all over their face and body language.) Sometimes I so amazed that they can't see past their own selfish desires to see how much they have to be grateful for. So today I'm reading about this word 'eucharisteo'. Inside this word is 'charis' which means grace and 'chara' that means joy. So I can't understand why my kids aren't bopping around in a constant state of gratitude and joy, while I have a festering annoyance and frustration just lying beneath the thin surface. This annoyance and festering comes out by provocation of my children's complaints. I guess I find it easy to be thankful for the obvious things...."thank you God for my family, my friends, and all that you provide." But still, the lack of joy.
"On the night that Jesus was betrayed, the Lord Jesus took some bread and gave thanks to God for it." Wait. On the night of His betrayal, and impeding torture and death....He gave thanks. Am I really grateful? If my gratitude isn't producing joy in the midst of what I considering frustrating and annoying (not even in the midst of betrayal), then am I really living in true thankfulness?
Paul wrote, "I have learned how to be content with whatever I have. I know how to live on almost nothing or with everything." I always read this with material living in mind. But, today I read it..."what is the nothing I think I living with?" If I'm irritated for what seems to be no reason, I must think I'm missing something. What is the "everything" I living with? I've been told I have everything I need in Christ. Now it's time for me to open my eyes to this "everything" and give thanks and embrace the joy of this grace.