I hope all of these instances of perceived frequency congestion are included in voyage reports, ASRs or CHIRPs. Don't forget that next time you might need to shout MAYDAY at someone.
One of the questions often asked regarding the rather grey area of 'ATC overloads' is, "could you have safely handled an emergency with the volume of traffic in your airspace"? If the RTF is so busy that a distress, or a PAN call cannot be made, it adds a whole new dimension to the proceedings.