There are people who will laugh and cry with you. They'll be emotional, they'll compliment you a lot, and they'll easily carry on conversations with you. Some people are emotional and aggressive, but they aren't consistently so, and their emotionalism and aggressiveness shouldn't be mistaken for love. A person who works quietly and consistently, with the right motives and objectives, may have more true love than somebody who's always wearing his heart on his sleeve. Don't pray for other people out of bitterness, pride, vengeance, selfishness, etc.
Nobody is perfect, and even our best efforts are often marred by sin.
But ask yourself why you're praying for other people and what you should be praying for. If praying for the person is just a vengeful reaction meant to show yourself as the better person, don't pray for him until your attitude has changed. Obviously, some people will be on your heart more than others and will therefore be mentioned more often and more passionately. And all of us have imperfect memories and limited time and strength. We should be persistent in prayer, but only as far as our limitations, our convictions, and our priorities can take us.