I really do think about this from time to time as to why we ever even used this word. I grew up the same as you where we all said it and used it as a replacement word for "ass" in situations where cussing wasn't allowed but you needed a word that hit a bit harder than calling someone stupid. I can't ever remember a time anyone I knew using it as a slur because someone would beat your ass if you got caught bullying anyone disabled. Now that I know that it is offensive I don't use it. But for me it's a bit weird fully relating to the current perception of the word in today's society because I still have mostly positive memories of goofing off with friends associated with it.