It, obviously, also helps that Danny Boyle was able to reunite almost everyone from the original Trainspotting to get back together again.
These themes tie directly into why Danny Boyle waited to get T2: Trainspotting off of the ground in the first place.
By waiting to make this film, the cast and crew were able to experience something far more personal, and it elevated the final product.
Ewan McGregor was obviously the biggest actor, but his reunion with actors like Ewan Bremner and Robert Carlyle makes the long-awaited sequel that much more poignant and painful to watch.