Main takeaways—

1. Commonplace syntax should be easy to type
2. // for comments is easier to type than #
3. Python’s indentation style is easy since you only need to use TAB (no end or {})
4. JS/C# lamba expressions using => are concise and easy to write
5. Short keywords like for in let var are easy to type
6. Using . for attributes (Python) is superior to $ (R)
7. >> is easier than |> or %>% for piping
8. Ruby’s usage of @ for @classvar is simpler than self.classvar
9. The ternary operator ?: is easy to write because it’s at the bottom right of the keyboard

Takes into account only US keyboard layout, but interesting anyway.