An excerpt from "So Long, and Thanks For All the Fish" (Adams Chp20). A brief story about biscuits.

"I was about twenty minutes early. I'd got the time of the train wrong. I suppose it is equally possible," he added after a moment's reflection, "that British Rail had got the time of the train wrong. Hadn't occurred to me before."
"Get on with it." Fenchurch laughed.

"So I bought a newspaper, to do the crossword, and went to the buffet to get a cup of coffee."

"You do the crossword?"
"Yes."
"Which one?"
"The Guardian usually."
"I think it tries to be too cute. I prefer The Times. Did you solve it?"
"What?"
"The crossword in the Guardian."
"I haven't had a chance to look at it yet," said Arthur, "I'm still trying to buy the coffee."
"All right then. Buy the coffee."
"I'm buying it. I am also," said Arthur, "buying some biscuits."
"What sort?"
"Rich Tea."
"Good Choice."
"I like them. Laden with all these new possessions, I go and sit at a table. And don't ask me what the table was like because this was some time ago and I can't remember. It was probably round."
"All right."
"So let me give you the layout. Me sitting at the table. On my left, the newspaper. On my right, the cup of coffee. In the middle of the table, the packet of biscuits."
"I see it perfectly."
"What you don't see," said Arthur, "because I haven't mentioned him yet, is the guy sitting at the table already. He is sitting there opposite me."
"What's he look like?"
"Perfectly ordinary. Briefcase. Business suit. He didn't look," said Arthur, "as if he was about to do anything weird."
"Ah. I know the type. What did he do?"
"He did this. He leaned across the table, picked up the packet of biscuits, tore it open, took one out, and..."
"What?"
"Ate it."
"What?"
"He ate it."
Fenchurch looked at him in astonishment.
"What on earth did you do?"
"Well, in the circumstances I did what any red-blooded Englishman would do. I was compelled," said Arthur, "to ignore it."
"What? Why?"
"Well, it's not the sort of thing you're trained for is it? I searched my soul, and discovered that there was nothing anywhere in my upbringing, experience or even primal instincts to tell me how to react to someone who has quite simply, calmly, sitting right there in front of me, stolen one of my biscuits." "Well, you could..."

Fenchurch thought about it. "I must say I'm not sure what I would have done either. So what happened?" "I stared furiously at the crossword," said Arthur. "Couldn't do a single clue, took a sip of coffee, it was too hot to drink, so there was nothing for it. I braced myself. I took a biscuit, trying very hard not to notice," he added, "that the packet was already mysteriously open..." "But you're fighting back, taking a tough line." "After my fashion, yes. I ate a biscuit. I ate it very deliberately and visibly, so that he would have no doubt as to what it was I was doing. When I eat a biscuit," Arthur said, "it stays eaten."
"So what did he do?"
"Took another one. Honestly," insisted Arthur, "this is exactly what happened. He took another biscuit, he ate it. Clear as daylight. Certain as we are sitting on the ground."
Fenchurch stirred uncomfortably.
"And the problem was," said Arthur, "that having not said anything the first time, it was somehow even more difficult to broach the subject a second time around. What do you say? "Excuse me...I couldn't help noticing, er..." Doesn't work. No, I ignored it with, if anything, even more vigor than previously."
"My man..."
"Stared at the crossword, again, still couldn't budge a bit of it, so showing some of the spirit that Henry V did on St. Crispin's Day..."
"What?"
"I went into the breach again. I took," said Arthur, "another biscuit. And for an instant our eyes met."
"Like this?"
"Yes, well, no, not quite like that. But they met. Just for an instant. And we both looked away. But I am here to tell you," said Arthur, "that there was a little electricity in the air. There was a little tension building up over the table. At about this time." "I can imagine." "We went through the whole packet like this. Him, me, him, me..." "The whole packet?" "Well it was only eight biscuits but it seemed like a lifetime of biscuits we were getting through at this point. Gladiators could hardly have had a tougher time."
"Gladiators," said Fenchurch, "would have had to do it in the sun. More physically gruelling." "There is that.
So. When the empty packet was lying between us the man at last got up, having done his worst, and left. I heaved a sigh of relief, of course. As it happened, my train was announced a moment or two later, so I finished my coffee, stood up, picked up the newspaper, and underneath the newspaper..."

"Yes?"

"Were my biscuits."
"What?" said Fenchurch.
"What?"
"True." "No!" She gasped and tossed herself back on the grass laughing. She sat up again.

"You complete nitwit," she hooted, "you almost completely and utterly foolish person."