Some commenting is too intrusive and interrupts the flow of reading the code. Examples for that are the /////////////
or /*****************/
hard-rules that some people put in their code, the comments using multiple slashes like ///
, or excessively long comment block. Please avoid all those.
Some schools of software engineering argue that if the code's author feels that a comment is needed, it usually indicates that the code is not clear and should be factored better (like extracting a method or a subroutine with a meaningful name.). It probably does not mean that you should avoid writing comments altogether, but excessive commenting could prove as a red flag.
If you're interested in documenting the public interface of your modules and command-line programs, refer to tools such as Doxygen, which may prove of use.