I attended a conference this week on forgiveness. One aspect of forgiveness is that people tend to forgive in direct correlation to their view of God. If they view God as kind, compassionate and forgiving they are much more likely to be the same toward others. Along those lines I've heard it said that every person develops into their image of God. If you think God is harsh and judgmental, odds are you too are a harsh and judgmental person.
It's always a bit confusing when I come across people who say that God is loving and forgiving yet they aren't that way themselves. There's a disconnect there that they don't even see. If they are honest about what they really believe about God, they'd admit that deep down they believe God is harsh and condemning. And that is why they are the same way. They are created in their image of God. Who they say God is is just a cover up for what they really believe. Until they discover this disconnect they are dooming themselves to being harsh and condemning themselves. It's too bad because they could be experiencing a totally different life - a joyfilled, peaceful life - but their view of God is shutting them off from that.
So, it's worth a look. If you find it hard to love and forgive others, check what you really believe about God. Ask him to reveal your heart and show you what's true. And then ask him to reveal his true self to you.