Remember the cartoons where a character would have a tiny angel on one shoulder telling them the right thing to do, and a little demon on the other telling them it would be far more cool to be nasty somehow, e.g. get their own back, be selfish, greedy. The two sides might be ‘eat your greens’ v ‘the chocolate is much nicer’, or ‘your mum would be upset if you arrive home late’ v ‘this party is really going to be fun soon’. There are a million possibilities.
Enter artificial intelligence, which is approaching conversation level, and knows the context of your situation, and your personal preferences etc, coupled to an earpiece in each ear, available from the cloud of course to minimise costs. If you really insisted, you could make cute little Bluetooth angels and demons to do the job properly.
In fact Sony have launched Xperia Ear, which does the basic admin assistant part of this, telling you diary events etc. All we need is an expansion of its domain, and of course an opposing view. ‘Sure, you have an appointment at 3, but that person you liked is in town, you could meet them for coffee.’
The little 3D miniatures could easily incorporate the electronics. Either you add an electronics module after manufacture into a small specially shaped recess or one is added internally during printing. You could have an avatar of a trusted friend as your shoulder angel, and maybe one of a more mischievous friend who is sometimes more fun as your shoulder demon. Of course you could have any kind of miniature pets or fictional entities instead.
With future materials, and of course AR, these little shoulder accessories could be great fun, and add a lot to your overall outfit, both in appearance and as conversation add-ons.