For me, it was Pokemon Special.
Still fond of the Yellow arc, because that was the first arc that I read. (I happened upon it when browsing books in the library, and read it out of curiosity because, well, Pokemon. I found afterwards that this was the "Best of Pokemon Adventures Yellow" volume, so it was actually condensing 4 volumes of content into 1 volume. I found some Chuang Yi scans online, and when I read the uncondensed version, the story made a lot more sense. Soooo much better than the anime.)
When Viz finally localized the manga past the Yellow arc here where I live, I was like, yay, finally. Bought all of the volumes up to the end of the Diamond and Pearl arc. Dat censorship though. No pokeboobs, and the motherly get-ahold-of-yourself slap turned into a motherly get-ahold-of-yourself glare. ¯\_(ツ)_/¯