After Marshall kicks Lori out for a cake mishap—she brings a cake with the wrong age and name—Lily realizes through an old photo that she was once the "random" girl in Marshall's life who might not have worked out, leading her to soften her stance. Key Subplots and Gags
Fans on Reddit often debate this episode, with many siding with Lily. They argue that bringing a stranger to an intimate birthday dinner is a major social faux pas, regardless of Ted’s optimism about "the one". Perspective on the Episode [S5E18] Say Cheese
The primary plot revolves around Lily’s birthday celebration. Tensions rise when Ted brings a date named Lori to the intimate dinner, a woman Lily suspects will just be another "random" girl who eventually disappears from their lives. After Marshall kicks Lori out for a cake