To jog your memory, see promises to concentrate on a second term as Mayor of London only to contest the safe seat of Uxbridge and South Ruislip in 2015 and that figure on the side of the Brexit bus promising extra cash for the NHS.
More recently, Johnson promised his constituents that he would fight the proposed third runway at Heathrow tooth and nail, even stating that he would lie down in front of bulldozers to prevent the work taking place.
So when Theresa May called for a whipped Parliamentary vote on the issue, prompting at least one ministerial resignation on a point of principle, Johnson made the political calculation that he could suffer a few days of the slings and arrows of social and traditional media opprobrium, save his job as Foreign Secretary and avoid delivering on his promise by simply not turning up to vote.
However, this appears to have been a reputational misstep too far for Johnson, who endured fierce criticism from within and without his own party during an opportune visit to Afghanistan to avoid the issue.
It remains to be seen whether his constituents will ditch him at the next general election for reneging on his promises (his majority last June was a strong but not immoveable 5,000). Or, like the less powerful member of a dysfunctional marriage, they may give him one more chance.
Johnson, whatever his protestations to the contrary, is known to covet the top job in British politics, but this latest cynical breach of trust with his constituents - and his failure to anticipate the tone of press coverage - could prove his future undoing.