People from a different culture coming to where I live without invitation, not adjusting to local norms, trying to bring their own norms with them and force those on local population, doing horrible crimes and, most often, escaping without punishment or after a "slap on a wrist" to return later for more.

Like, "severing child's head and walking around downtown with it, blood dripping, while screaming ISIS claims" horrible.

I would really like to stop that, bonus points for sending as much of them home as humanely possible, and then holding people who let this happen in the first place direly accountable.