הידור מצוה
Succot is also known as the holiday that teaches us the concept of הידור מצוה, or, glorifying the Mitzva. This is learned from the words from אז ישיר that says, זה א-לי ואנוהו, this is my G-d and I will adorn Him.
We learn from here how we show that we love the Mitzvot. We are supposed to invest time and money to try to purchase the nicest Lulav and Etrog that we can afford. We also examine the Four Species to look for blemish free Arba Minim. We also try to invest our time and money in building the most beautiful Succa that we can.
A good test of our commitment to Judaism is our willingness to beautify and adorn all of the Mitzvot that we perform. We are never to view Mitzvot as a burden. And we are never supposed to regret monies that we spent in performing Mitzvot. All of this is learned from הידור מצוה and זה א-לי ואנוהו.