I wondered how easy it would be to recognise a persons face as “angry” and put a cloud over them in the augmented world. This could be fun, but at the same time would actually be really useful for people who have problems recognising emotions – e.g. people with autism. This could help them as they could look through the augmented world and understand that the cloud is there, therefore that guy is angry.
On the flip side, you could help awareness of people who don’t recognise emotion by making the app recognise a face and blat a generic deadpan face over the top. So people try to do their daily interactions without facial queues.