The Rambam in Hilchos Yesodei HaTorah says God has no joy or sadness. If so, why do we wait for moshiach? For G-d's glory? G-d does not need anything from us. How are we supposed to have intent to give nachas to G-d when he doesn't even care?
This excellent article by Rabbi Aron Moss explains why G-d created the world if He is perfect and lacks nothing. The crunch of it is that G-d does not need us, but he want us. The only thing G-d did not have before creating the world was a relationship with someone else (because there was nothing else but Him). Moshiach is the epitome of our relationship with G-d.
For further reading I would recommend this lengthier article by Rabbi Tzvi Freeman "What is the Purpose of Existence?", and this collection of articles on the topic of G-d's purpose in creating the world.