Standing in the biting cold outside Castle Buildings on Thursday afternoon, a colleague entertained us with a story about the Ulster Unionist leader. Someone on his desk had written a mildly unflattering profile of Mr Trimble, describing him in passing as somewhat "irascible".
The next day, so the story ran, the journalist took a call from a plainly annoyed Mr Trimble, demanding: "What the hell do you mean describing me as irascible?"
True or false, the story conformed to a certain stereotype of the Upper Bann MP. Some of his senior colleagues certainly find Mr Trimble at times complex and difficult. They have also found him pretty much "unknowable" - and never more so than in the final build-up to yesterday's historic Irish-British agreement.
Indeed, until just the past few weeks, that very "unknowability" has provided for further humour at Mr Trimble's expense. Asked if he knew why Mr Trimble had sought the party leadership, and what he intended to do with it, one opponent replied: "I don't think he knows himself."
But it has become increasingly apparent over recent months that that "unknowability" was a key element in Mr Trimble's conduct of the most delicate and complex set of negotiations ever to confront a modern unionist leader.
He has had to conduct them, moreover, against a dramatically changed political landscape in Britain which - from a unionist perspective - may have appeared to offer few prospects and many dangers.
Mr Trimble inherited the leadership from James (now Lord) Molyneaux amid a growing unionist perception that he had been overly-reliant on his relationship with Mr John Major, while failing to exploit the Conservative leader's escalating parliamentary predicament.
However, Mr Trimble found himself dealing with a Labour prime minister with a commanding Commons majority and the near certainty of a second term before him. The scale of Mr Blair's election triumph can only have encouraged nationalist and republican hopes that London would finally put "the squeeze" on the Ulster Unionists.
That has not been the nature of the Prime Minister's dealings with Mr Trimble but things might have been very different had the UUP leader not taken the decision last September to side-step the decommissioning barrier and enter the talks process with Sinn Fein.
Mr Adams is almost certainly right to say that the scale of progress might have been even more significantly advanced had Mr Trimble "engaged" directly with him and his party. But the risk he took last September cannot be easily exaggerated - as last night's rumours of the potential scale of the split within his party must amply confirm.
The Sinn Fein president was also right when he characterised Mr Trimble's engagement with the process as purely strategic. So it was in the first instance. And, as the months dragged by, the suspicion grew that the UUP leader was engaged in little more than a blame-allocation exercise.
However, the evidence of yesterday's agreement, and its all-embracing inclusive scale, suggests Mr Trimble has come to accept that it might actually be possible to bring the conflict to an end.
And while yesterday afternoon's last-gasp scare over decommissioning paramilitary weapons brought a reminder of the potential hazards ahead, Mr Trimble's key decisions on the Strand One issues concerning the future government of the North have opened the door to Sinn Fein's direct involvement at ministerial or executive level in the North's government.
Earlier this week, the Alliance Party couldn't understand Mr Trimble's rejection of its plan to form an executive by way of a coalition - effectively themselves, the SDLP and the UUP - commanding a weighted majority. This would have vanquished Sinn Fein and the DUP to the opposition benches.
In the end the hero of the Garvaghy Road met the SDLP's demand for the inclusive approach.
And if Mr Trimble's demand for reassurance about the sanctions to be deployed against any party not adhering to purely democratic means - and the need to effect the decommissioning and other confidence-building measures envisaged by the Mitchell Principles - has spelt out crudely to the paramilitaries that participation in government comes at a price, he has hardly performed a disservice to democratic society.
By any standards, Mr Trimble has made a bold gambit. As the howls of protest gather around him, he could be forgiven for pondering the price he might yet pay.