It arrived like it were a vaccine or a new high-speed mobile data network, promising to take us into a future when we would not be able to conceive of a time without it, in football's case when a referee had to rely on just his eyes and his instincts to run a match.
That was VAR just a year ago. Now, at the end of another bad week in a season in which there have, at times, been calls to junk the whole experiment, you wonder how one man alone in a room with access to so many replays can still make the referee feel like he is on the wrong side of the argument. What happened to the tech solution that once promised an end to error?
The great problem of VAR lies partly in its protocol, revised over and again by its author, the former referee David Elleray, now the International Football Association Board's technical director.
His reluctance to give proper veto over the on-field referee colours the whole process.
It lies also with the clubs, worried about the delays caused by referees making on-field reviews in front of pitchside monitors.
One year on, the problem that has been realised is not the initial fear that video assistants would try to re-referee games, rather it is that the nature of the protocol that requires them to play detective with the minds of their on-field colleagues.
Last week, aggrieved managers turned on individual video assistant referees rather than the system itself. Jose Mourinho on Michael Oliver. Dean Smith on Graham Scott. Just as last month in a post-match interview, David Moyes demanded to know the identity of the VAR - David Coote - who failed to spot a handball by Davinson Sanchez following West Ham's defeat by Spurs.
The system is failing the referee both as on-field official and as VAR. Under the Ifab protocol conceived by Elleray, VAR is not asked to adjudicate right or wrong - rather it is asked to scrutinise the motives of the on-field referee in arriving at his decision.
"The referee's original decision will not be changed," says the Ifab protocol, "unless there was a clear and obvious error."
On Thursday night, the video assistants at the centre of three errors in three Premier League games had to marry the headset testimony of their on-field colleagues to the footage of the incidents they were rewatching.
Then they had to decide whether what had taken place amounted to a "clear and obvious error" rather than whether the decision was correct.
This is the life of the VAR, be it Scott on Villa Park duty or Oliver reviewing the action at the Vitality Stadium. They can see the pictures we see on replay, but via the headset they listen to the explanation from their on-field colleague as to why he gave the decision. From then on, the VAR is a detective trying to match the evidence to the explanation and deciding whether there is a big enough gulf between the two for an intervention.
Often, as in the case of Bruno Fernandes's penalty at Villa Park on Thursday, there is a strong sense from the VAR that a mistake has been made.
But having heard the on-field referee's view of what he saw, VAR has to decide whether it reaches the "clear and obvious" threshold.
It becomes one referee's opinion against another - and the tendency will always be to err in favour of the on-field decision.
The majority of English select group referees - fulfilling on-field and VAR roles - want the whole process simplified. For subjective decisions like the severity of a foul for a red card, or a penalty, they do not want VARs to have to concern themselves with whether a clear and obvious error has been made. They would rather the VAR simply recommend an on-field review.
Chris Kavanagh undertook one on Tuesday before correctly upgrading Eddie Nketiah's yellow card for a challenge on James Justin to a red.
VAR can work. The protocol has to change to allow it.
After one year of huge upheaval in the English game's decision-making process and mistakes made in the Premier League and elsewhere in Europe, abolishing "clear and obvious" would be a step forward. Whether change happens with the decision to take control of that process by Pierluigi Collina, Fifa referees' committee chairman, remains to be seen.
Covid-19, too, has had an effect on the life, and possibly the performance, of the VARs at Stockley Park. Before the pandemic they were able to socialise freely before they went to their individual rooms. On a Saturday, they would often gather to watch the 12.30pm kick-off and share their opinions on the decisions made. It was a chance to develop camaraderie around the thanklessness of their task and to talk about what had gone wrong and what had gone right. Now they do not see one another, and each VAR goes straight to his designated room.
It is the isolation of the VAR that makes his decision so difficult. He reviews incidents alone, apart from a replay operator and an assistant, who are not there to confer. The doubts can creep in. His instincts are naturally those of an on-field referee making decisions afresh. But in the VAR room he is being asked to referee the mind of his on-field colleague.
In Elleray's day as a referee, the assistants were known as linesmen and there was no fourth official. The referee was king and there was not the level of detail in replays or the depth of analysis to make him seem as foolish as the modern referee can be made to look.
By using technology, VAR was intended to restore the referee to a position of power in the information age - or, at the very least, parity. And yet it has diminished him.
The idea remains sound - a sensible review system that gives referees a second chance and the benefit of the replays the viewer sees at home. But the execution of VAR has been a disaster at times, and the "clear and obvious" rule is at the heart of a flawed protocol.