PB&J

"A lot of people told me I was crazy to wait this long for a date with a girl who I worked with, but I think, even then I knew, I was waiting for my wife."

- Jim Halpert about Pam Beesly, Niagra: Part I 6x04

PB&J is the Het ship between James "Jim" Duncan Halpert and Pamela "Pam" Morgan Beesly Halpert from The Office fandom.

Canon
Jim and Pam's friendship had caught the attention of the documentary crew filming the Dunder-Mifflin Scranton branch right from the beginning. Their constant playfulness and quick, adorable exchanges hinted that they may have deeper feelings for one another.

Pre-Series
The first moment Jim knew he liked Pam was when she told him to forever remember the moment before he met his future desk-mate, Dwight who Jim would eventually share a frenemy-like relationship with. Jim also claims that his best "first date" was with Pam as they shared many things in common. This only lasted until the moment Jim realizes that Pam was engaged to Roy and their lunch was just between friends.

Later in the series, Pam admits to Jim that she knew she liked him when he made a funny comment on her mixed berry yogurt which had expired. Unfortunately, at the time she mostly denied her true feelings for Jim and only saw him as her best friend for many years because she was still engaged to Roy.