IT'S not the journey.
It's not even the arrival. It's the way back that's proving the problem for Celtic. Their sojourns into Europe are taking a very heavy and expensive toll.
With four Champions League qualifiers, two play-off ties and an opening Europa League group stage match behind them, the cost is being paid through their domestic commitments.
And there are five more such potential Euro-night hangovers to prepare for.
Already this season on the back of European matches, Celtic have lost to St Johnstone and been held to a draw by Dundee.
Now, on the back of their visit to Austria in midweek to play Salzburg, they dropped another two points to Motherwell.
To their credit, the Hoops did mount a huge effort to fight back from going a goal down in the first half to a goal from John Sutton.
But they had enough of the ball and created enough chances to hit back with more than just a Kris Commons penalty won by Scott Brown when he went down in the area under a challenge from Josh Law.
Nevertheless, the record books will only show the game finished 1-1, and that's what really counts.
These are further dropped points which, over the course of the campaign, Ronny Deila will be confident they can claw back.
However, since they elected to take the opening day of the domestic season off to help them cope with the stresses and strains of the Champions League qualification programme, his side have been playing catch-up.
And not to the usual suspects. Instead it is Dundee United, Inverness and Hamilton who are the surprise packages topping the table in these early stages of the campaign.
Given that Celtic went 25 games in last season's league programme before they finally tasted defeat, at Aberdeen at the end of February, it is yet another contrast between Neil Lennon's days in charge and what is occurring under the new man, who has made it clear he is intent on lifting all three domestic honours and going deep into the Europa League. The next couple of weeks will provide an acid test for those ambitions, with Hearts on Wednesday a threat to their League Cup aspirations and Dinamo Zagreb rolling into town the following week on the back of their opening Group D demolition of Astra while the Hoops were eking out a point in Salzburg.
There can't be too much confidence coursing through the corridors of Celtic Park, not when the results of the past month-and-a-half are laid before them.
Since their demolition of Dundee United on August 16, Celtic have won just one of the seven games contested in the league and in Europe.
That was the 2-1 victory over Aberdeen nine days ago, a match which saw them hanging on in the closing stages after looking on course to a comfortable win.
Against Motherwell, it was a polar opposite performance, the visitors having taken the lead through Sutton after Anthony Stokes had lost possession, then retreating into a defensive shell which proved very difficult to breach.
The half-time appearance of Commons and Brown for the ineffective Beram Kayal and Aleksandar Tonev was a tacit admission that Deila's six changes from midweek was taking squad rotation too far.
The Norwegian wants to find out what he has in reserve, but results like this one and the defeat at Inverness confirm it's not as much as he'll have been hoping.
The one-win-in-seven stats don't lie, and the manager recognises it is not acceptable for this club.
Certainly, the draw with Motherwell was not the birthday present the now 39-year-old wanted, and he said: "Of course I want to win every game.
"We need to get more victories in the league (they are now fourth in the table, five points behind the leaders) and also win cup ties, or else we will be out of those competitions.
"But I think we are in control. We have made a good start in the Europa League, we are in both cups, and we are still fighting well in the league. I know things will be better and better. So I am just looking forward to the games now because I believe we are improving."
There was no great evidence of that against Stuart McCall's rebuilt side, re-energised after a poor start to the season.
The club which has finished second for the past two seasons is always a tough nut for Celtic to crack.
But when the Hoops are devoid of imagination and creativity, as was the case yesterday, it leaves the door wide open for shock results.
When he got his players inside at the interval, Deila did not spare anyone's feelings, and Tonev and Kayal were just two of many players who might have been taken off.
Deila admitted: "The first half against Motherwell was not at the level where we want to be, but the second half was much better."
While the manager must ultimately carry the can for how the team performs, the individuals involved must also take responsibility when performances fall below what is acceptable to the paying support, which as the boos at half-time and full-time confirmed is very much where we are now.
Deila acknowledges his Bhoys have to act like men when confronted by such a well-drilled outfit.
"They have to do it themselves in those circumstances," he said, as he reflected on their first-half performance.
"There are a lot of new players, so I understand that it takes time to adapt, but we need more people to play to the level they can."
Failure to do just that could lead to further problems against Hearts on Wednesday.