In every Moffatt-era episode of Doctor Who, the plot is the same. Something bad happens, and then the badness unfolds to the point where all seems to be lost, for instance probably a lot of the characters involved are literally dead, until someone has an Emotion so powerful it tears apart the space-time continuum somehow and all the badness is fixed forever. The implication is clear: your sadness is a weapon. All you need to do is wield it properly.
A parallel trend can be observed in the ‘Harry My Cat Died’ phenomenon. Teenagers on twitter bombard members of One Direction, Justin Bieber, etc. with messages disclosing personal sadness, bereavement, disaster and so on in a nakedly cynical attempt to get their idols to follow them back. This is, for them, all that sadness is good for: a means to acquiring the desired status of being someone, for instance, that Harry Styles follows on twitter. Not for them the quiet and meditative dignity of a process of private mourning. Bring it all out in public, where it might be useful.
The weaponisation of emotion is something that is, in this country at least, enshrined in law. As has been pointed out recently in connection with protests surrounding Margaret Thatcher’s funeral, section 5 of the Public Order Act allows police to step in (i.e. violently) if non-violent action is the cause of “harassment, alarm, or distress,” i.e. to the mourners as people protest Thatcher’s funeral. Sadness, here, is on the state’s side, and it not only trumps joy in the sphere of politeness: the Thatcher family’s sadness at their dear old mother/grandmother/whatever’s passing can literally be used to legitimate police brutality.
Part of the issue here must be that Emotion as such is established in discourse as something that cannot be questioned by others. The reason why sadness has ‘trumps’ is that it is a personal, private thing that we must be respectful towards. This would be fine if mourning (for example) really was allowed to be a private process. But not only is this never really allowed anymore; for the teenagers of ‘Harry My Cat Died’ the emotion (if real) only strikes them as a (public) opportunity to get something out of it that they want. Moffatt’s Doctor Who reinforces this: Emotion always wins out because the firmest warrants are the ones you get by feeling, privately, the most. Actual physical violence, in this sense, starts to seem in fact less coercive, more like a rational move in a debate. After all, it can at least be questioned with more violence. I suppose the only way we could combat the coercive forces of Emotion is by trying to feel more than they do. But unfortunately, it seems, in for example the Thatcher case, we can never trump their sadness with our joy.