While it is normal to test at certain ages and stages, don't let this become an excuse to not deal with the behaviours. It sounds like you are doing your best, but the mom who said her child said she hated the gift and then wouldn't talk to her friend for the rest of the party...and she didn't know what to do? I would have laid down the law right then and there. That is extremely rude behaviour and no age or stage justifies it. I would have told the child to apologize and thank her friend for the gift and include her friend in her play or she could spend the rest of her party alone in her room...and I would be serious! Just because it's her birthday does not give her the right to be rude. I recently went to a birthday party of a school friend of my 5 year old. The child opened all of her gifts without saying one thank you...I was horrified! Parents really need to step up to the plate and teach their kids how to behave properly and politely (not saying you don't do this...it was the birthday story that got me going..LOL). There need to be consequences for being mean...it is not acceptable. You can remove priveleges, etc if you find them teasing. Just telling them will probably not have much effect until they feel the consequences of their actions.