There's Thankfulness, and Then There's Extreme and Complete Thankfulness

Klal Yisroel fought wars against its enemies, but the main war of a person is between your Yetzer HaTov and your Yetzer Hara (Chovos Halvavos¹) which are symbolized by Yaakov and Eisav. Of course, Yaakov overcame the Malach of Eisav, and Eisav and his 400 men disappeared and left Yaakov alone. וַיָּבֹא יַעֲקֹב שָׁלֵם וישלח לג יח Yaakov came out “Shalem” (whole) and a total winner. What is the difference between Yaakov and Eisav? Eisav says: יֶשׁ לִי רָב וישלח לג ט I have MOSTLY everything, and Yaakov says: יֶשׁ לִי כֹל וישלח לג יא I have EVERYTHING. (Chofetz Chaim²). At first glance they don't seem so far from each other (what's the difference between everything or mostly everything?). However, the extreme and complete thankfulness is a totally different world.

Dovid is special because he sang and thanked despite his Tzaros Netziv³