Let me ask you a question: "Do you want to live to fulfill that whatever you do, you do it for the Lord?". You'd probably answer yes to this.
Then why do you refuse the best and say "What I already have is good enough"? This can be said about anything. I'm not telling you to crave material things, no, that'd be wrong of me. Love your God with all your heart and love your neighbor as you love yourself, is what Jesus tells us.
But if you have given your heart to Jesus and truly love him and your neighbors, then why not go for the best? You agree that whatever you do, you do it for God. Then why can't we serve him with excellency?
Again, don't get me wrong! I'm not telling you to be ungrateful of what you already have. No, don't do that. Be thankful to Him. But it isn't wrong to ask God for things. As long as your focus is on God (and I believe it is), then ask him of what you feel in your heart you want. And don't worry, if he doesn't want you to have whatever it is, He'll say no :)
We all know the story of Cain and Abel.
Abel brought the firstborn of his flock to the Lord and that was his offering. Cain brought what - a bowl of salad?
Let's face it. Both brothers had the same privileges and rights. They had the same things to take from, yet Cain's careless attitude made him bring a careless offering.
Let's not serve God with a simple bowl of salad, but let's bring him the best we can, with the best we've got.
Because remember: "Blessed be the God and Father of our Lord Jesus Christ, who has blessed us in Christ with EVERY spiritual blessing in the heavenly places," - Eph. 1:3
He already gave us the best of the best. Sometimes we need to be patient - other times he wants us to ask Him for it and tell him in details what we want. We are, after all, His kids and He's our Dad :)