Tabuhans are able to pull stings from their stomachs so they can sting again and again. Hornet is a more aggressive natural predator. With a little provocation they will sometimes get angry and attack. If you are attacked by bees that are close to the nest, it will release a pheromone signal to a friend, then they will come out and attack you.
They are looking for nectar from various flowers to eat. They are zoogami useful in pollination. Bees are very rarely seen to investigate humans, unless there are flowers around it.