Perhaps you are familiar, with the series "The Lion, the Witch, and the Wardrobe", ? In this series, the Lion represents, God. Also, there is the Wizards of Oz, in which the Lion is a lost travelor, looking for the Wizard, to give him courage.
Perhaps, the roaring could be a man who has the quality, of a lion, but is all out of patience, with someone, who doesn't see him that way, a friend, or relative. We usually make our ultimatums, which that is, to our closest people. Perhaps, a man yelling at his wife, because he wants to try out a new adventure, some scheme, to make money, and he was doing this thing for a long time: having ideas that were adventures, to make money. Each time met with exasperation with the wife, as to why she wouldn't be behind him, and believe in him. Maybe some of the ideas made them, lose money, or get in trouble. But now, he's not taking this negativity, from his wife, or girlfriend, anymore. In his mind, he is a hero, a courageous, adventurous, brave lion. So he roars in anger, at her disbelief.
What do you think? Hope this stimulate your own thinking. Yes, I think you should go right, to the idea.
Hello,
This quote seems to be said in anger at someone. You could write about any relationship that is going through a difficult time, EX: a friend who repeatedly lets you down, a parent who was negligent, a sibling who always got into trouble and expected you to help them out.
One direction you could go in terms of meaning is how complicated human relationships are. We are constantly let down by the people around us, yet we continue to try to make our relationships with them work. Also, we let others down. Not out of spite, but just because we are human and make mistakes.
You could start the story off in a fight, and do a flashback type set up where you explain how the characters got into the current situation as you progress. Or you can start from the beginning.
I think you have the potential to write a very good story off of this.
Hope this helped