Political leaders can't help themselves. If they see a jugular, they go for it. It's in their DNA.
Take Tony Abbott and Bill Shorten on Wednesday.
In the morning they basked in the warm glow of bipartisanship on indigenous development as the prime minister delivered his first Closing the Gap statement.
No doubt they were sincere.
Yet a few hours later, when question time started, they were at it hammer and tongs - and initially on matters Aboriginal.
Shorten started by demanding to know why Abbott hadn't fulfilled an election promise to stay in East Arnhem Land in his first week as prime minister.
Abbott replied that people had misunderstood what he said, which was really that East Arnhem Land was the remote area he'd visit first. And he would, later in the year.
Shorten had more Arnhem Land ammunition - what was Abbott doing about Rio Tinto's decision to close its aluminium refinery at Gove, at the cost of 1200 jobs.
Abbott said he deeply regretted Rio's decision and understood why people at Gove were upset.
Then he counter-attacked: If Shorten was so concerned about the loss of jobs, the best thing he could do would be to have a word with his senators about passing the government's bill to repeal the carbon tax.
This provoked howls of protest from Labor. Warren Snowdon, whose electorate includes Gove, shouted "You just don't get it."
These exchanges won't affect bipartisanship on broad indigenous policy, but they show how precarious relationships between natural enemies are.
The acrimony continued, especially over just what a Toyota executive told Joe Hockey in December.
This goes to the government's preferred line that over-generous working conditions were a key cause of Toyota deciding to pull out of Australia.
Shorten also suspects Hockey of leaking a self-serving version of his discussions with Toyota to the media.
After making little progress, apart from provoking Hockey to shout "get your facts right, mate", Shorten moved to the censure motion gambit.
But the government wasn't about to give him the space to mount an attack.
Shorten just had time to call for Abbott to be censured for blaming job losses on unions and Hockey to be censured for giving a "false account" of his Toyota meeting, before being gagged.
About all he achieved was to lose nearly 20 minutes of question time.
