We know from the Scriptures that all of Creation glorifies God. We have all had that experience of feeling God's presence in the summer breeze, in the flittering butterfly, or in the brightness of the night sky. But all of these parts of God's Creation worship the Lord just by being themselves. Stars, sunsets, rainbows, waterfalls, all of these things are passive glorifiers of God, but our free will enables us to actively glorify God. The waves never have the temptation of not crashing into the rocky beach, the rainbow never considers not appearing after a spring rain. But we as humans are unique in that we can choose to worship God, we can become active glorifiers of the Lord.
The results of worship are available only to humanity. Drawing near to God, receiveing His protection, entering into intense relationship with Him, these are all benefits that only humans can receive. Is this a piece of what the angels "long to look into?" I thank God that he made me human!