After vanquishing all, just before the marriage supper of the Lamb, those before His throb fall down to worship and a voice comes from the throne saying, Praise our God.
For me the praise is not for what He has done. What He's done for me instills thanksgiving. That's not why I praise.
Praise is for His attributes, His capabilities - His omniscience and omnipotence. He is capable of creation and destruction. He is filled with judgment - perfect adjudication - as well as mercy and grace.
There is none like Him, though men define many that are supposed to be - or deny any exist, especially One who cares about His creation. He inspired Moses to write:
Exo 8:10b And he said, Be it according to thy word: that thou mayest know that there isnone like unto the LORD our God.
We praise because He deserves it.