When I was Bushido Brown, many people would say, "Oh, you're Afro Samurai!" Some people asked if I was "a generic Bleach enemy" and another [very drunk] guy followed me around while calling me Bruce Leeroy from The Last Dragon. I wasn't particularly offended by any of those. I don't think Bushido and Afro look alike at all, but I had already prepared myself knowing that I would most likely be called either at any given time.
The Best Times: At A-Kon, an older gentleman misidentified me as Jim Kelly (who half of Bushido is based off of) and told me this entertaining story about growing up in the 70s and how hip he used to be. He was a really nice guy. At ACen, a younger guy walked up to me and asked, "... Are you Bushido Brown?" I affirmed and he sighed with relief, "Oh man, my friends said I'd be racist if I asked you that." My response was, "Hey, man, I'm a blaxploitation character, my concept is based partially on racism." We all shared a laugh.
The Worst (but also kind of the best) Time: At A-Kon, one guy called me Afro Samurai and I told him I was Bushido Brown. He looked a bit puzzled and I added, "From The Boondocks cartoon." He laughed and said, "Oh yeah! Well, same difference!" I then responded, "Yeah, all us black people look alike anyway." He laughed, "Yeah, I know right!?" His friends looked absolutely horrified and immediately rebuked him. He did actually feel that way and it was a little bothersome, but I'm pretty sure he was drunk, too.
I saw a Sol-Badguy at A-Kon that I misidentified as Ragna the Bloodedge. He sounded really sad when he corrected me and I felt pretty bad for making the mistake. In my defense, I was Slender Man at the time and the mask obscured him a bit. All I saw was "ArcSys" and "red costume" until I looked again.