The only point in having your destiny in your own hands is if you know what to do with it.
And last night's Ireland display in a rain-soaked Geneva simply smashes apart the arrogance of assuming that Ireland's route to Euro 2020 is smooth, simple and in sight. Beat Denmark and the team qualify.
The team which played last night, on the basis of that evidence, will come nowhere near beating the Danes.
Take out the win over Gibraltar and the Ireland side have never looked like winning the last four qualifiers; and yet they'll find their feet, find their passes and find goals at home against the Danes?
That's fairytale stuff, when the team are delivering nightmare scenarios.
Ireland's best route to goal is a set-piece sent to Shane Duffy's head. The only problem with a tactic like that is, use it too often, rely on it all the time, and everyone gets to know about it. The Swiss knew it last night, the Danes know it. And it will still be our preferred route to the Euros.
This was Ireland's chance to try and play a bit, mix grit with guile, despite the poor playing surface. That guile was nowhere to be seen for most of the night, though things did look a bit better for a spell in the second half when Callum O'Dowda had come on for James Collins.
O'Dowda tried, Glenn Whelan shielded the back four with his usual unheralded effort, but, yet again, players like James McClean and Jeff Hendrick didn't stand up.
Collins is a player who looked so far out of his depth last night that playing him was close to punishment. We can only imagine what Shane Long, watching this game on TV at home in England, made of it all, seeing a Luton Town journeyman get two chances to start for Ireland in a week while Long was deemed not good enough for a 24-man squad.
The cult of the manager which Irish football gets caught up in all too often means the blame for this appalling night will fall on the shoulders of the Yorkshire native who is in charge of the side.
And he deserves some of the flack.
But McCarthy alone can't take the blame for Ireland's awful passing or the mistakes made by senior players.
We had a dose of that last night. The Swiss got their goal on 16 minutes, but it came about from a self-inflicted wound, McClean needlessly playing the ball out to touch and passing up possession.
A Swiss corner, which led to a great chance from Fabian Schar, came from a slip by Shane Duffy. And Seamus Coleman only has himself to blame for a second yellow card. Last night was such a tough evening for the captain, that it was hard to watch. The pitch didn't make it easy to stitch a run of passes together but the home side tried it, managed it.
Ireland? They hoofed when in possession, panicked with the ball at their feet. Accuracy and game-intelligence seemed to seep from the Ireland players into the damp turf of the Stade de Geneva.
McCarthy got a lot wrong this week. His pre-match comments about Connolly will have confused the teenager, and by talking about negativity and "peddlers of doom" back home, he simply opened the door of the dressing room for those critics. He's also getting it wrong with Collins as the player is simply not of international standard.
But the shocking levels of passing ability are not all down to McCarthy. He has been let down, repeatedly, by pallid displays from McClean and Hendrick.
Callum Robinson and Conor Hourihane were dropped for their Tbilisi displays and while Whelan needs to keep his place (things would have been grim without him), McCarthy needs to ensure some senior players, who have let him down, should pay the price. Passers of the ball like Josh Cullen need to be trusted as those who get repeated opportunities squander possession.
Qualification is still there for McCarthy. However, to do that, the team needs to beat Denmark at home. That's not a rescue mission, it's mission impossible. Ireland can't summon up a passing game in 90 minutes, and we can only think there's worse to come.