"Of course a betta can live in an unheated bowl with three goldfish! Make sure to change the water once a month!"
Ugh. I was this close to stepping in, but the customer was so rude to the salespeople already I knew that I didn't stand a chance.
*Holding one of those divided 0.5g 'tanks' and a healthy-looking betta* "Well let's see if this one lives for a week, and then we can think about getting another" *Walks out without conditioner, heater, etc*
At this point I just block out what everyone around me is saying; I have to look after my own sanity.