Psalm 141:2 ASV

How do our prayers smell to God.. do the stink with selfishness, pride or greed?.. or do the have the pleasing scent of our hunger for more of Him. it is easy to ask God for what we want.. But what about what He wants, or even more what He wants us to pray for.
I know that God responds to many types of prayer but how does He want us to pray..?