Genesis 1:25 New International Version (NIV)

25 God made the wild animals according to their kinds, the livestock according to their kinds, and all the creatures that move along the ground according to their kinds. And God saw that it was good.

When God had completed his work, he saw that it was good. He was pleased. God felt good about his work. Sometimes we may feel guilty for feeling good about an accomplishment, though, we should not feel good about our work if God would not be pleased with it. Make sure what you do is first pleasing to God, and if it is pleasing to him, it will be pleasing to you.