Obviously Japan. My first year there I actually was stupid and left my phone/keys at the table when I went to the toilet and things like that. After a while I realised that while the chances of theft are very small, they are not zero.

Was this in Shibuya? Maybe there or Roppongi, but most other places aren't really a worry.

Kyoto. But I disagree that it's not a worry. It only takes one opportunistic person to ruin your day (or month)