hmm well 2 1/2 is typically a hard time for kids. I read a book "Raising your spirited child" that suggests that behavior typically deteriorates as a child approaches his or her birthday or half birthday as the are getting ready to make developmental leaps.

When my kids are having a hard time I try and gently remind them that hands are for hugging and kindness. Then point out they made the other child very sad. 2 year old often have a budding sense of empathy and it can work wonders to point out others feelings