As soon as Indian Foreign Minister SM Krishna landed in New Delhi, he had to respond to unusually personal accusations from his Pakistani counterpart, Shah Mahmood Qureshi.
Supposedly Krishna had gone to Islamabad unprepared, had kept phoning back to India for instructions, and generally acted as a diplomatic layabout.
After Krishna's defence, a senior Indian diplomat, asked if Qureshi's decision to let loose even before Krishna had left the country was an unprecedented act.
The diplomat responded: "They've done this before."
Boorish behaviour has been remarkably common in Pakistan's official interactions with India.
Zulfikar Ali Bhutto was famous for using four-letter words when he spoke to an Indian across a negotiating table. His daughter Benazir Bhutto's unparliamentary language when she talked of the then Prime Minister Narasimha Rao still rankles with Indian diplomats.
The Islamabad talks foundered when Qureshi tossed aside weeks of preparatory talks and, after lunch, suddenly asked India to sign up for a time-bound solution to Kashmir and two other issues (peace and security, and Siachen).
This is another Pakistani speciality: ambush diplomacy.
Pervez Musharraf had tried the same tactic at the Agra summit, personally scrawling off-the-cuff proposals and demanding Atal Bihari Vajpayee sign the dotted line.
Indian officials who have been across the table from Pakistani delegations are unsurprised at what happened in Islamabad.
How did the Pakistani School of Diplomacy come into being?
Those who have been at the receiving end say the most important reason for the way Pakistan behaves is that the ultimate levers of powers are held by soldiers. The military stamp, says former foreign secretary Kanwal Sibal, "tends to make Pakistanis brash and overbearing at talks. They look at complex issues without nuance and behave with a certain swagger."
It also means that, unlike in India, Pakistani negotiators contend with two centres of power. This muddies their ability to focus on the long term.
"When negotiating with them, it is necessary to first ascertain which principal they are answering to," says an Indian diplomat who handled talks with the Pakistanis for years.
"Except for three brief periods, there has only been one centre of power in Pakistan, the other was a façade."
A certain geopolitical environment has encouraged Pakistan in its curmudgeonly ways.
"Their experience has been that they can get away with this sort of behaviour," says Sibal.
For much of its history, Pakistan has been able to count on more international support than India — whether it has been the West, the Islamic world, East Asia or even the rest of the subcontinent. This has given Pakistan the leeway to break the diplomatic rulebook, something that has now become a habit.
"Foreign assistance allowed them to play a role greater than their actual capabilities," says G Parthasarathy, former high commissioner to Pakistan.
The result: a nuclear-armed spoilt kid of a nation.
India is not the only recipient. Bill Clinton's special envoy, Strobe Talbott, wrote how he felt physically threatened during his talks with a Pakistani official.
John F Kennedy had one Pakistani ambassador turfed out of Washington after the latter upbraided him about his Kashmir policy. His successor gifted Jacqueline Kennedy a diamond ring as a "peace offering".
The years have also seen a coarsening of the Pakistani polity. Islamic fundamentalists and the military have an outsize role in the national discourse. Neither group puts much store in the rounded corners of diplomacy, with its culture of compromise seeking and emotional restraint.
Pakistan's politicians and bureaucrats earn brownie points if they play to these two galleries. Qureshi's antics were largely for a domestic audience he felt needed appeasing. But Pakistan also believes it can exploit India's social fissures.
One goal being served by savaging Krishna, writes B Raman, former Pakistan analyst of the Research and Analysis Wing, "was to create doubts in the mind of the Indian public about the credibility and professional competence of Mr Krishna."
Mind you, there is little evidence bullyboy tactics have served Pakistan well. Few leaders were as effective as promoting Pakistan's interests than Zia ul Haq, a dictator who cultivated a false humility and avoided brashness. And today, says Raman, Qureshi's behaviour is visible to the whole world.
It will make "the international community understand the kind of Pakistani leadership we have to contend with".
"Their behaviour has provided them tactical gains that have ended in strategic defeat," says Parthasarathy.
He cites the example of 1962, when the senior Bhutto bombarded the then Indian Foreign Minister, Swaran Singh, with verbal abuse during seven rounds of negotiations.
"Sardar Singh never lost his cool throughout," he says.
"But Singh had the last laugh: In 1971, after Pakistan's defeat, he forced a weeping Bhutto to leave the United Nations Security Council."
Read about the eight points of Indo-Pak composite dialogue .