"Trouble" he knew best from when his mother warned him not to steal Batman croc charms from the Stride Rite bin.
But the actual meaning of the other "trouble" he came to know without really knowing the word for it: the way his mother could look even during one of his thumb magic tricks.
Maybe she could look that way because she knew how the plastic thumb worked, having bought it for him herself. But he had taught himself new tricks, and she liked to see them except when she was cooking dinner or picking up after him. "I'd have time for tricks, if you'd hang your coat up yourself. ..."
So he tried to pick a time when she wasn't busy – after she'd just hung up with his elderly grandmother and she was just sitting at the table. She'd been bent into the phone, trying to explain something about a Visa card: "No, Mom," she'd said. "You can't do that, just charge the balance back to your card. That's why you're getting charged interest. You need to write a check, from your checking account..." Her forehead would be resting in one hand. There were other such phone calls, as when his grandmother couldn't open a precooked chicken.
But when she was just sitting there at the table, staring at the wall, he decided she wasn't busy and he could show her his new thumb trick.
"Sure," she said, sounding tired. She folded her arms on the table to play audience. Yet she wasn't as attentive as on the phone. She pretended surprise when he whipped a tissue out from behind her ear. Then she just looked at him as blankly as she had stared at the wall.
He slipped his thumb back into his pocket. Maybe he should have done one of his disappearing coin tricks instead. But by the way she still sat there even after he left the room, he didn't think it would have mattered.