One of the first things the new MPs entering Parliament following September's election will quickly learn is the necessity of growing a suit of armour, one preferably of tungsten-like durability.
Sooner or later, they will find themselves subject to verbal abuse. Some of it will be witty, a lot of it will be weak, most of it will be within the boundaries of acceptable behaviour.
This year, however, has witnessed a departure from the norm. The day-to-day political banter has been infected by a sudden nastiness.
Twice in the past week, MPs have crossed the line between being tough and being outright distasteful.
The first example came from a surprise quarter - the Greens. Jan Logie, a first-term MP, tweeted on last week's Budget, noting that "John key says Bill English has produced as many budgets as children ... Begs the question who he has f****d to produce it" [sic].