Mara is a photographer and dress salesgirl with a fear of commitment who nonetheless finds herself getting into a serious relationship with a diner cook named Jake. They receive invitations to fifteen weddings in one year and give thought to their relationship while attending them. Sarah Hyland, Tyler James Williams, Anna Camp, Keith David, Patrick Warburton and Jenna Dewan appear in the film.
- Accidental Misnaming: Mara repeatedly calls Ellie's husband by Ellie's ex-boyfriend's name.
- Alcohol-Induced Idiocy: Mara meets Jake's ex-girlfriend Nicole at the first wedding, then gets drunk out of insecurity, challenges Nicole to a dance-off while barely able to stand, yells at Nicole to stay away from her man, and throws up in the champagne bucket.
- Bridezilla: Downplayed with Mara's coworker Ellie. Ellie and her wedding party get sick from bad food at the rehearsal dinner and Ellie gets very hostile when the groom suggests canceling the wedding reception, while snapping at him for ordering the food that got them sick. By the wedding itself Ellie has calmed down, and she is understanding during Mara's cringeworthy, unrehearsed maid of honor speech (the original maid of honor was too sick to attend the wedding).
- Drinking Contest: Because they can't afford to travel to fifteen weddings in one year, Mara and Jake get into a drinking contest for each wedding that only one of them wants to attend, passing out at least once in the process. They ultimately narrow it down to seven weddings.
- Gay Best Friend: Mara's closest friend and confidant is a gay man named Alex.
- Gilligan Cut: After getting the fifteen wedding invitations, Mara decides to break up with Jake due to not wanting to commit for a whole year by agreeing to go to all of them together. It cuts to Mara's house as they have an Immodest Orgasm, with Mara having changed her mind.
- High Heel Hurt: When Violet runs out of her wedding, Mara chases after her and yells for Violet not to make her run in high-heels. A little bit later Mara has to take her shoes off, and walks with a limp for the rest of the scene.
- Obnoxious In-Laws: Jake's parents and grandmother unfavorably compare Mara to Nicole and make pushy I Want Grandkids comments. Jake's new sister-in-law also finds them suffocating, to the point where she almost cancels her wedding. Mara's unhappily divorced parents also make Jake somewhat uneasy.
- Post-Stress Overeating: After running out on her wedding to Robbie, Violet goes to a fast food joint and downs three and a half cheeseburgers.
- Second-Act Breakup: Jake and Mara break up after the last wedding due to an argument about their future (complete with her Returning the Wedding Ring), but get back together after some time to themselves.
- The Stoner: Mara is constantly vaping throughout the movie.
