What made you the angriest you've ever been in your life? How angry were you? For how long? What did you wish you could do about it?
Now: is there any way you can channel this energy, this fervent wish and feeling, into a story?
"Sebastian was vexed. Not only did his favorite wand break, but it also left a gluey mess upon the floor of the cave, which had trailed after him as his multicolored garment dipped into it like a long multicolored paintbrush. It was now impossible to remove, and glowed with an annoying light both day and night."
Perhaps this imagination was poured from the chalice of this situation:
"Fred was mad. His favorite television remote fell apart in his hand and leaked battery acid on the carpet, eating little holes here and there. And the holes weren't in inconspicuous places, either. No, they were right in the middle of the floor where everyone could see them. Everyone, including his wife. Even with the lights out and a dim TV the only luminescence in the room, they could still be seen."
Though this is more of a frustration than a fervent seething anger, the point remains the same: real circumstances translate nicely into fictitious situations and lend a taste of credibility to which your readers will relate.