I remember a site that only prohibited certain special characters ($, #, %, /, \, *, ;, decimal point (.) and comma (,)), but others were fine. I remember it because usually sites prohibit all special characters or just a couple.

In most cases i see an difference in the special characters.

password rules make very little sense except for minimum number of characters.

when you impose rules on a password you also imply a list of non-possibilities.