As mentioned on The Always Sunny Podcast, this episode is based on an actual event where Glenn Howerton's vehicle was hit while he was eating cereal.
The first and only time throughout the series where a patron drinking at Paddy's Pub says goodbye or thanks the gang in any way.
When Mac says, "Rock, Flag, and Eagle! Right, Charlie?" he's referring to S02E09 when Charlie sings himself an inspirational song about America ending with Rock, Flag, and Eagle.
Dee mentions that the gang has destroyed every car she's ever owned. When in fact during the 'Gang Hits The Road' episode her car was stolen by a hitchhiker.