Nadine O'Regan: A new rule of thumb

We’ve all been there. Someone shares something sad and awful on Facebook, the revelation, perhaps, that their grandparent has died; or they have to emigrate to Australia; or that they’re frantically worried because their beloved cat has gone missing – and then you do the stupid thing. You press the button that says you ‘like’ this post they have shared. Then you look at the screen and that glaring thumbs up icon, and ...