More quirks involve using semi-colon instead of /* */.

If the semi-colon is not in the last command of the line, then it's commenting just itself, and the following command gets executed. But if the last command of the line is commented, a curly-brace at the end of that line also gets ignored by the code, but it's not ignored by Ctrl+H checking for mis-matched braces. This situation is also not friendly to an "else" condition on the next line. It took me a long time to trace down a similar error in a script because the code was behaving as if there were mis-matched braces, but Ctrl+H didn't complain about it.

Code:
alias testcomments {
  echo -a yes 1 | /* echo -a no 1 */ | echo -a no 2
  echo -a yes 2 | ; echo -a no 3  | echo -a yes 3
  if (1) { echo -a yes if condition $true A | ; echo -a no 4 | echo -a yes if condition $true B }
  else echo -a yes if condition=false
  if (1) { echo -a yes if condition $true C | ; echo -a no 5 }
  else echo -a not displayed regardless if condition (1) or (0)
  echo -a the rest of this alias is ignored when 2nd if (condition) changed to: if (0)
}