Grew up saying 'pop' but later on hung around people who said 'soda' enough that it became 'soda' or 'soda pop'. 
This one is really interesting for me because it's a major bone of contention in Wisconsin...and the map reveals why!
I say marry, merry, Mary all the same as well. My MIL is Marie pronounced almost like Mary, but not quite. I can hear how it's different, but not imitate it. DH says it's the same as marry, which doesn't help.
I also pronounce shore, sure, and Shaw differently, but the people I work with (British) pronounce them all the same.
Good stuff
