McGee violated Delilah's dinner table rules.
The dinner table rules in the McGee-Fielding household are simple: You are only allowed to talk about work for an allocated amount of time during what is called the "dinner download." Once the timer goes off, you must move on to more "boring," regular conversation topics.
While McGee typically follows the rules, one night he couldn't help but ramble on about a particularly perplexing case. To make matters worse, he used the meal Delilah spent two whole hours preparing to recreate the crime scene!
Watch the high-tension dinner take place in "After Hours" (Episode 17, Season 13 of NCIS) on CBS All Access.