There was one time back in 2015 or so an older lady got into a screaming match with an unruly group in front of me in line for the Astro Orbitor. It escalated with one member of the group loudly exclaiming "Don't make me come over there and whoop your a** b****!" Still have no idea what the fight was about (the lady wasn't in line).
Obviously, incredibly uncomfortable for everyone around. Disneyland is no place for violence-both verbal and physical, attitude, and profanity. I feel bad for any children in Toontown who had to witness that fight, and will now have that kind of memory tainting their impressions of Disneyland. I'm typically not bothered by profanity, but at Disneyland it REALLY rubs me the wrong way, especially if said loud enough for others outside your group to hear.