Letter columns were a big deal for me. The best letters would maybe clue me in on what happened in an issue I missed and or insight in the reply to a letter. Sometimes the response would be a tantalizing tidbit of something coming up. Usually a TM Maple letter was good one. I even bought Charlton Bullseye because it had good letters imho. For some reason my drugstore carried that short run anthology and while I only wanted superheroes I found myself enjoying horror/funny animal and sci-fi issues too. It never took long to read a comic book but Charlton Bullseye had several pages of letters usually! As for best letters, there was one letter that I liked so much I wrote the person and we ended up being pen pals for many years and still stay in touch to this day.
