Jesus died on a torture stake not a cross.
Jonah was swallowed by a big fish not a whale.
Adam and Eve ate the fruit not an apple.
JWs observe the memorial not celebrate Easter (yet both occur coincidentally close to each other and concern Jesus' death/resurrection, hmm...)
We were always careful to say John the Baptizer instead of John the Baptist. Baptist for some reason was a taboo word.
Along with the ones NikL mentioned, it all just seemed so nit-picky to me growing up. Church or kingdom hall...who cares? The kids I went to school with also knew about Moses, Noah, the Garden of Eden and believed in Jesus just like I did. How was that possible if we were the only ones with the "truth"? The more JWs brought up how different we were, the more similarities I saw. I could never buy into "all roads lead to one god" so I finally concluded they were all wrong.