Sing praises unto Him; speak of all His wondrous acts.
Exult in His holy name; let all who seek the LORD rejoice.
Turn to the LORD, to His might; seek His presence constantly.
Thanks and Gratitude.
The Hebrew phrase for "thanks" is HaKarat Hatov which means "recognition of good." I read recently that gratitude is an expression of modesty. I had never really thought of it in those terms. Interestingly, the Hebrew word for gratitude is hoda'ah which happens to be the word for "confession." To offer thanks is to confess dependence, that others have the power to benefit you. It is to admit that your life is better because of their efforts. Let me repeat that. To recognize good in others is to admit that others have the power to benefit you. It is just me or is that a powerful concept? Recognize the good and confess/realize the dependence we have on others. For humanity, it models Oneness.
Think about this now in terms of G-d, however it is you may envision the divine. Giving thanks to G-d shows our gratitude. Recognizing G-d's goodness is an act of confessing that he has the power to benefit us. Admitting he has the power to benefit us. Look, this may not be such a big concept to you, but for those of us who struggle and wrestle with the notion of what G-d is and whether or not he intervenes in this world, it injects a whole new level of meaning into the prayers.
Each time I am giving thanks to G-d on Shabbat, morning prayers, grace after meals, etc., this concept adds a layer of vulnerability, a suspension of the mundane, a brush with the mystical. When I pray "Thank you G-d" I am really expressing "You have the power to benefit me."
"Thank you G-d for returning my soul to me." (I confess my dependence on you.)
"Thank you G-d for giving life to my children." (You have the power to benefit me.)
"Thank you G-d for all of this beauty that surrounds me." (My life is better because of your efforts.)
It is said that Rav Yechezkel Abramski (zt"l) would pause as he entered his home in the evening and contemplate everything his wife had done for him that day--and only then did he enter.