This is the first chronological appearance of Gale Boetticher, a prominent character in Breaking Bad (2008).
When Mr. Neff orders a pizza, he requests that the pizza be sliced. This implies that it is the same pizza place that Walter White ordered from in Breaking Bad when he throws the pizza onto his roof it's un-sliced. Also Badger mentions that the pizza place doesn't slice the pizza and passes the savings onto the customer.
A hint of Gale Boetticher (David Costabile)'s singing ability was demonstrated in Bullet Points (2011), as found in a karaoke video shown by Hank to Walter and his son Junior in Breaking Bad (2008).
The song that Gale is singing and listening to is "The Elements" by Tom Lehrer. "The Elements" is a song by musical humorist and lecturer Tom Lehrer, which recites the names of all the chemical elements known at the time of writing, up to number 102, nobelium. It was written in 1959 and can be found on his albums Tom Lehrer in Concert, More of Tom Lehrer and An Evening Wasted with Tom Lehrer. The song is sung to the tune of the "Major-General's Song" from The Pirates of Penzance by W.S. Gilbert and Arthur Sullivan.