Couples will never forget the moment they become engaged, but not always for the reasons they imagine.

No, some couples will forever remember the moment they agreed to marry because nothing went according to plan. Maybe the proposal was interrupted by a photobomber, or the groom-to-be accidentally knocked his girlfriend to the ground. Or, in some cases, maybe a small child started urinating in the background, only to be noticed after the proposal ─ and the aforementioned urination ─ is well underway.

Whatever the case, these were the most memorable engagements of 2018, for better or for worse.

Groom-to-be proposes with child peeing in background

Let’s just get this one out of the way right now.

In May, Michigan resident Kevin Przytula popped the question to girlfriend Allyssa Anter, and a camera was there to capture every second. Even the part where Anter’s son Owen begins peeing on the ground in the background.

"I just started laughing, this is what Owen does," Anter later told WNEM 5.

"This is our everyday life, that's what we deal with on a daily basis," Przytula added.

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Cyclist photobombs engagement shoot

(SWNS)

Kentucky resident Blake Martin planned to propose to girlfriend Shannon Keene on a quaint bridge in Louisville, and he even hired a photographer to capture the exact moment he dropped down to one knee to propose.

Unfortunately, a nearby cyclist didn’t notice what was going on until it was a little too late, and whizzed by at that same exact moment.

"I had been planning this proposal for about three months," Martin said of the Nov. 9 incident. "I was extremely nervous. It all happened so fast. I got down on one knee and this orange blur just zipped by and screamed 'Sorry.' It was nuts."

Groom-to-be picks awkward time to propose

Dennis Galvin couldn’t have picked a more inappropriate time to propose, according to the Internet.

Galvin made headlines in November after asking his girlfriend Kaitlyn Curran to be his bride — in the middle of the New York City marathon, which Curran was participating in.

Curran, who appeared to be visibly shocked, gave Galvin the answer he was hoping for, but critics on social media weren’t as nice. "He couldn't propose to her at the finish line?" one critic asked. Another theorized that “his male ego was too small to let her get all of the attention for even a few hours.”

Despite the backlash, Curran’s cousin said the duo were both “happy” with how things turned out.

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Grandpa films engagement, but only technically

A New Mexico grandpa looked overjoyed to be tasked with recording a couple’s proposal, but what he didn’t realize was that the camera was on selfie mode and he only recorded his own reaction.

John Hart met the soon-to-be-engaged couple in July while riding the Sandia Peak Tramway near Albuquerque. The Navy veteran was later asked to record the strangers’ engagement by the groom-to-be himself, but apparently, he didn’t know how to work the camera phone.

The couple broke out laughing after learning of Hart’s blunder, and Hart can be heard describing himself as a “turkey” right after the incident.

Guy knocks girlfriend to the floor during unexpected proposal

What was meant to be a romantic proposal had a minor setback when one man accidentally knocked his girlfriend to the floor right before popping the question.

Kyle Pierce planned to propose to Jenna Eller in the middle of her college volleyball match at Concordia University in Seward, Neb., on Oct. 30. But just as Pierce enters the court, Eller dashes after the volleyball and runs directly into him, the collision knocking her to the ground.

“We’ve had a lot of memorable moments in this gym, but this one is by far my favorite,” Pierce later said of the incident. “Thanks to everyone that made this happen!”

Dallas Mavericks fan photobombs proposal, scores himself an invite

Keith Houseworth decided to propose to his girlfriend Panda Green during an October Dallas Mavericks game against the Utah Jazz. And no one was more surprised than some guy in the background.

As seen on the jumbotron ─ and TV ─ fellow fan Jonathan Miller hopped out of his seat and quickly stole the show, staring directly into the camera with his eyes wide and mouth agape, in total shock.

The footage went viral, and Miller later earned himself an invite to the couple’s wedding.

"I did not think it was going to go past being on the Jumbotron, honestly," Miller later said.

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Alexandra Deabler, Janine Puhak, Michelle Gant and Michael Bartiromo contributed to this report.