I would say bars, overall, including knifings and fist fights.
Convenience stores would be in the top 2 for the clerk, because he/she is always there. Whereas for you or me our infrequent visits lower the probabilities to unlikely.
Back this last New Years Eve I brought a bunch of snacks to our local bar for a midnight party, as did many others. One person there was however trying to pick a fight with me. He was so drunk he could hardly speak, and he was wearing tennis shoes. I was stone cold sober and was wearing motorcycle boots and was armed.
He would not have stood a chance. First I would have crushed his toes then I would have slit his you know what.
But I let it go, and eventually he shut up.
So, bars. Definitely.