Ya goofed. Pulled the wrong merge info, or, maybe no merge info at all so your subscriber is left with something like |MERGE FNAME|. An apology or oops email is a great way to let your audience know you sent them the wrong message and you're trying to make it right. Depending on the subject matter, you can use this as an opportunity to send a playful or humorous message to your audience and let them know you'll do better next time.