I started with the C64, and moved to an Amiga, and it felt effortless to move from the 6502 to a 68k. When I years later for the first time sat down with x86 asm it immediately motivated me to stop programming assembler.

Despite being incredibly dissimilar, the relative regularity of the 6502 and 68k felt familiar - a small set of rules and patterns flowed naturally into implementing quite complex code in a way it didn't on the x86. It's remarkable how much those things matters.