There's the joke about the old bull, the young bull and the herd of cows. We needn't go into it, but yesterday we saw a number of bullocky new members trying to nail their target, asking their first question in the first Prime Minister's Questions of the first coalition for generations. The parliamentary herd hardly noticed them speaking.
And then Labour's lefty Ian Davidson stood up in a leisurely way and nailed them all. "Comrade Premier," he hailed the new young Prime Minister, and suddenly everyone was laughing (that's all it takes). "What," he asked, "aren't we all in this together?" (More laughter). And then he named the binding, unifying force in Britain as how "the vast majority disliked, distrusted and despised the Liberal Democrats".
The Tories roared, Labour roared, actually even some Liberal Democrats laughed. Nick Clegg laughed in a way that wasn't actually laughing (it's the Third Way). There's no equivalent sally yet about the Tories, so it probably infringed the bullying code of conduct. Oh well, never mind.
Labour wasn't working, much. They're absorbed with their own problems of leadership, tone, position. And maybe it's all going to be more serious than they'd feared. It was going to depend on how David Cameron did.
There's no necessary reason to suppose he'd be any good at being Prime Minister. There's so much you have to have at your fingertips when you're suddenly in the new job, you need to know all sorts of things all the time in a way nobody else has to.
Shootings in Cumbria, school places in Derbyshire, bankers' bonuses in Afghanistan, body armour for terror teachers' classroom assistants, tackling the root causes of the married man's tax allowance for under-age binge drinking rape victims. Most of us would hear these sorts of questions and reply with: "Yes, good point, let me think about that."
Actually, Cameron did say exactly that, and to Harriet Harman. I fancy a little cloud passed over the collective face of Labour at that moment as they started to worry that their position as "the progressive consensus" might have been whistled away from them.
Harriet asked a number of questions; they didn't cause problems so much as provide opportunities. She was more Iain Duncan Smith than William Hague.
But it was when Cameron said, "I know she cares very deeply as do I" that Labour unease started to flicker. "We all want the same thing," he went on, persuasively. Gordon Brown used to demand angrily that his opponents "join the national consensus". It was a threat more than an invitation. Labour saw Cameron lighting up a television screen where Gordon used to darken it.
Harriet got in a good jab about the marriage tax allowance that provides a manky £3 a week but will cost half a billion quid. Cameron won this with a return of serve involving Labour's change to inheritance tax (some gasps at the audacity). Without going into it, he finished with the words, "If that was such a good thing for the well off why can't the less well off have it too?" Tory pleasure was most sincere, but Labour fear was surely the sweeter for the PM.
Cameron may not be as thought-through as Tony Blair. He's not as briefed, as programmed, as strategically positioned. There's an upside to that. A decade ago, having lunch with Tony Blair in a group of people, it was like watching him on television. He was so scripted, he was untouchable.
Cameron still has his sense of self. Affable, amused, confident, got all his own fingernails and an easy sense that he's doing the right sort of thing.
Important thing: he's not constantly trying to get the opposition on the wrong side of the argument. That instinct was the first, second or third requirement in everything the previous prime minister said, did, planned.
This one isn't driven by the hatred of his opponents. It's early days yet, of course, but let's enjoy the sunshine while it lasts.