I have always liked ~ for string concatenation. Looks like a little string tying the strings together, and hardly likely to be confused with the bitwise not operator.
I thought about it, but for the most part I used `~` as a way of referring to something in an unstrict way, e.g. `~+` doesn't typecheck, it just adds and auto-coerces both operands to a number.
I didn't want to have `~` mean string concat because it overloads the semantic meaning of what `~` would represent.
I actually stole `&` from VB, as well as `\` as floor division.
