You anoint my head with oil;Anointing the head with oil could mean two different things. It could be referring to his kingship, and that his head was anointed as king. But according to the context of the passage, it more likely referring to the favor that is being shown to him. We can see in the New Testament how anointing with oil can be a sign of respect for an honored guest.
my cup overflows.
As you read through this passage, you can get the real sense of the author culminating to this point and almost being at a loss for words. He gets to this point in his writing and just begins to use these short statements. He is amazed at the favor that the Good Shepherd shows him and finally wraps it up by saying, "my cup overflows."
The word overflows means literally saturated. It would be as if you were talking about how good something is and then said, "...it's... it's just too much."
So many of us miss the saturated lives we live because we are wrapped up in the little picture, and not seeing the big picture of God's love. We get focused on the valley of the shadow of death, and forget that the Good and Great Shepherd is leading us through this and saturating us with His love. Trust in Him today, He is leading you in the paths of righteousness.