Sam shut his eyes and slumped in his seat, cringing. The kids in the front of the bus were laughing, and he had a hunch who they were laughing at. “Look at that old lady’s umbrella!” someone said. Sam jerked upright. Oh, no. She hasn’t! He looked. She had. This was worse than he'd thought. There at the bus stop was his grandmother with her new umbrella. The jumbo-sized one that was neon pink; the one she’d bought from the shop up the road, exclaiming “Oka, lima tala!” over the bargain price. Sam shook his head in misery. The other kids jostled and shoved to get off. But Sam took his time, dragging each foot.
11. What is the most likely cause of Sam's misery?