Most small kids will have fits of anger, during which there is barely any point in talking to them, as they are unable to process your input (scolding/cajoling/etc). In my opinion, the best way to deal with this is to just wait it out as stoically as you can, maybe move them to a place where they are less of a disturbance to others (to reduce the likelihood that their judgment will affect your own actions). After the anger has passed, talk it out. Definitely don't reward tantrums, in fact make it clear in advance that tantrums will get them less, not more. I don't think there is a magic solution, it's part of raising a kid.