"But first, we need to talk about parallel universes." [i]Oh my god,[/i] I thought, [i]he's starting with [/i]that[i]?[/i] "I hate you so much," I whispered as my head thudded softly against the laminate of the table. "Are you okay?" he asked, concern in his voice. I let out a groan, and looked up balefully. "You're picking up the check, right?" "Sure?" My hand shot up, waving the waitress over. "Two milkshakes, please." "One strawberry," he chimed in. I glared. "Three milkshakes," I clarified. "Two chocolate one strawberry, double cherries on the chocolate, none on the strawberry." "I like cherries too." "I [i]know[/i]," I said icily. "Okay, but listen," he said, placing our straw wrappers next to one another on the table. "If you think of all the possibilities in a given moment, there's an ever-expanding multiplicity of outcomes. Not just whether you move to one city or another, or even order a chocolate or strawberry milkshake. What if a tiny speck of dust settles one millimeter to the left? It's not like that [i]matters[/i], sure. But it's not like the universe knows what... matters." He crooked his fingers in air quotes and paused, waiting for some acknowledgment. "I'm breaking up with you," I offered. "No, no, not until you hear me out. This is important." He leaned over to the booth behind him to grab another pair of straws. "So you have an infinite number of—well, maybe not infinite but unimaginably large number of parallel universes, right? Only the ones that are closest are indistinguishable. Maybe a single atom millions of light years away has decayed slightly faster and that's the only difference. But since they're parallel there's no way to get from here—" he jabbed at a wrapper "—to there." He laid down another straw next to it. "Yes. I've taken high school geometry." "Parallel universes are interesting but even if we were able to shift one planar micron to the side, we'd hardly even notice. So that's why we also need to talk about [i]perpendicular[/i] universes." He laid a straw crossing over both of the other two at a right angle. "Mmhmm." I pulled out my phone, tapping on the app for twitter. "Go ahead, I'm listening." Twenty minutes and two milkshakes later, I quit cycling through my bookmarks and put my phone back in my pocket. He was winding down, it looked like. Halfway through he had raided a few more booths and now the expanded straw structure at the center of our table included salt shakers balanced on a napkin dispenser and a whole section made of interlocked silverware. He had gotten excited enough to bend a spoon in some tangent on temporal displacement, and I idly wondered whether the diner would make him pay for that or if they just expected patrons at this time of night to have a few screws loose. "And so [i]that's[/i] why I disappeared last night," he concluded. I slurped loudly at the remains of my second milkshake and waved the waitress over to bring me a glass of water. "And I got you this." He pushed a small box across the table, almost knocking over the salt shakers in the process. I raised an eyebrow and cracked the box. Inside was a ring, with a small gem inset that shimmered and glowed in rainbow hues. "It's like a mood ring. Matches colors with—" I frowned as the rainbow colors drained out, the gem taking on the appearance of glass. "Oh. Maybe it's broken? I can see if—" "Tell me," I said. "What exactly did you miss last night?" He grimaced. "Your birthday. I'm so sorry." I closed my eyes and smiled. "My birthday was last week. Last night was dinner with my parents. But hey, I understand how you got the two mixed up because [i]you missed my birthday too, you incredible dick.[/i]" He stared at me, eyes wide as I dumped the ring into his half-full milkshake with a [i]plop[/i]. "I'm so, so sorry. It's just... things get so confusing what with the—" "The parallel universes, right. Well, I have good news." His smile returned, dazzling with hope. "Yes?" "That means that somewhere out there in the innumerable universes there's a version of me that's stupid enough to forgive you." I dumped the glass of water out all over his pile of straw wrappers and stood to leave. "Good luck finding it."