Enemies: to be blessed or cursed?

I am still searching for a better explanation on: "are enemies to be loved (Matthew) or hated (Psalms) ?".

I tried to reconcile Matthew and Psalms saying that some enemies are to be hated (or at least avoided) and some are to be loved. I said that even in New Testament some people are to be avoided: mainly the ones who deserted Christian faith. I compared them to Judas Iscariot who walked with Jesus searching for his own interest. 

It is one way of thinking but there must be more. It is still a shallow thought because, even the other disciples were walking in hopes of being great leaders over Israel, sitting besides Jesus. So, it seems to me, that in a sense, I myself, am following Jesus for my reward. This is not bad at all! This is approved by Jesus! A son that obeys his father is, in a way, seeking his benefit because the father wants the best to his children. The problem is what a man treasures more.

Judas sold Jesus in order to get money. He made a terrible deal: he exchanged the great pearl for a tiny pearl. However, other disciples didn't do the same. They were almost loosing hope when they saw Jesus nailed at the cross. They got lost and went back to fishing wondering how much injustice had been done to the One who fed people, who walked on the sea of Galilee, who made them see the Lord of the Universe. 

The Lord is good. He created us to be his people, his chosen ones. He wanted to share his creation with us. In fact, He subjected his creation to the dominion of men, but the men rebelled against the Lord, and became evil, sinner, against the will of the Lord. 

Men are to subject themselves to the Lord and care for creation like a gardener who aligns his will with the owner of the garden.

However, men decided to take the garden and use it to themselves for their evil desires. By doing so, they rebelled against the Lord, becoming his enemies. Corrupted men became slaves of money, sex, power. In some sense, instead of having dominion over the creation, the creation had dominion over them. Men treasured more the creation than the Creator becoming his enemies.

Are enemies (Lord's enemies) to be blessed or cursed?

In Ephesians 6, we read:

12 For our struggle is not against flesh and blood, but against the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms.

According to Ephesians, it seems to me that we should pray for everyone, even to some "Judas Iscariot" that we may encounter in our lives because our fight is against the spiritual forces of evil. Is it a good conclusion? 

In Psalm 139 David says that he hates the enemies of the Lord, that he sides with the Lord against some people. Should this people include Saul or Absalom? Saul and Absalom were loved by David even though David killed many people like Philistines and the Canaanites. Saul and Absalom were much closer to Judas Iscariot than the Canaanites. 

Well, I am still wondering: are there some human enemies to be hated? How to proper read Psalms? I don't think there is an easy answer to this question, but let the Lord guide me when reading Psalms. I want to read it according to his will and I want to see how Matthew and Psalms complement each other. 

Love is the great commandment because it reflects our Lord. He is a loving God. Let me love as the Lord wishes. 

However, let me also hate as the Lord wishes (as I am trying to understand Psalms). I will continue showing people that were cursed in the New Testament.