I work at a grocery store where we employ multiple people who have down syndrome. One of our female baggers with DS will tell you what she is placing in each bag as she bags your order. One day, a gentleman was checking out and she stated to him what she was placing in each bag and after each time she spoke to the man he would say ok I heard you the first time. This persisted for around a minute before the man said "I fucking heard you". I heard this, I am a team leader so I was in charge of the staff that day and I strolled over in a very calmly and said the the man sir please do not use that language in this grocery store. He replied to me quite angrily saying "tell this dumb bitch to stop telling me what she is bagging and just do it". I replied very quickly in stern voice and said "sir it is obvious that you do not notice that she suffers from down syndrome, she is one of our best baggers and no amount of apologies can justify your language and attitude towards her or anyone for that matter". The customer then looked down at the ground for the rest of the order and has not set foot in the store since.

Tl:dr guy cursed at bagger with down syndrome, I told him about his lack of observation skills and his poor attitude.