No Place For Me There: Again, the Fifth Directorate.  They may be necessary monsters¹, but they know that they’re monsters.  Retirement from the Fifth involves an extensive memory wipe and having the traits that made you useful to them and dangerous to everyone else wiped away, a degree of mental editing which is almost always enough of an abolishment of identity to be legally equivalent to suicide.

[1] In the exact and precise sense of the trope page quote (which is copied below), taken from the Operative in Serenity. Except, mark you, that the Alliance is merely a conventional democratic government along our familiar Earth-type lines – which is to say, by Imperial standards, an appalling sédármódan crypto-tyranny – which should give you some idea of how big the I’m-a-monster complexes of the equivalent people whose baseline is an actual bona-fide Society of Consent grow to be…

The Operative: I believe in something greater than myself. A better world. A world without sin.

Capt. Malcolm Reynolds: So me and mine gotta lay down and die so you can live in your better world?

The Operative: I’m not going to live there. There’s no place for me there, any more than there is for you. Malcolm… I’m a monster. What I do is evil. I have no illusions about it, but it must be done.

— Serenity