In football there are two main reasons why transfer policy goes badly.
The first involves knowing what you want, but not having the means to get it, and often settling for less. This is a pretty simple dilemma that all but about seven of Europe's top teams will be familiar with - a case in point would be Spurs wanting Sergio Agüero in 2012, but through lack of means ending up with a 32-year-old Louis Saha.
Ok, that was a rather extreme example. Most clubs have certain constraints to work under, and through clever scouting can find a second or third-choice player who perfectly fits the niche that they've identified.
The second dilemma, and one which often has much more consequences when it goes wrong, applies mainly to those select clubs which do have the means to sign almost any player in the world.
This dilemma could roughly be described as not knowing what you want from the transfer market, and making things worse by pretending otherwise.
What's the relevance of this distinction? Well, it's one that has to be made when we talk about the struggles that both Barcelona and Atlético Madrid have experienced in finding someone to lead their line.
Atlético Madrid and Barcelona have the same problem - a lack of a prolific central striker who is worth an extra 10-15 goals a season - but they are not the same.
It's very easy to make fun of Atlético when it comes to goalscoring, and they don't help themselves - when your 5-0 win over Osasuna is the first such margin of victory in over two years, you might just have to live with the stereotype you've created for yourself.
They're third in La Liga but are the league's seventh-highest goalscorers, and their own best-performing forward in said league, Álvaro Morata, has just ninth goals. Clearly, there is an issue here.
But the issue is largely connected to the gambles that a team like Atlético has to make when they need a new number nine, alongside other mitigating factors in the background which effect every football club.
Two years ago, they needed a hard-working, combative striker to act as the perfect foil to Antoine Griezmann. They decided that couldn't afford to risk a considerable outlay on a 20-year-old Lautaro Martínez, and turned to Morata as a cheaper option.
If it works, fantastic. If not, try again, as Atlético could well with Napoli's Arkadiusz Milik this summer.
that's the reality of being just below the elite tier of European football - shaping and gradually perfecting a model as best your means allow.
The most important thing is that neither the player nor the club needed to compromise this philosophical model, and Morata ended up front and centre of Atlético's most important moment of the season as they stunned Liverpool at Anfield.
Indeed, Morata alone can't be blamed- his strike partner has changed from Griezmann to the young, still-adapting, João Félix, and in a broader sense it has been a season of transitions for Atlético - club stalwarts Diego Godin and Juanfran have gone out alongside Griezmann, and Marcos Llorente, Renan Lodi and Mario Hermoso (to name just a few) have all come in alongside Félix.
With established players either underperforming at various points in the season, with Koke a particularly surprising example, or in the case of Thomas Partey and Saúl Ñíguez, looking to move on,
Atlético's main responsibility is to protect their identity throughout this tumult.
In essence, Atlético Madrid have not done business at the expense of a functional team, and it feels as if they only need some small adjustments to go back to a sharpened version of their old selves - whether it be Félix's acclimatisation or a savvy deal for Milik.
Barcelona, meanwhile, look nothing like themselves at the moment in attack (other than Messi, obviously), an aberration which can be explained by them not having the slightest clue what kind of player they're after.
The La Liga champions make it very clear that they do everything with their club's abiding philosophy in mind - down to signing 2018's 'Most Cruyffist Manager' Quique Setien to manage them.
Unfortunately, they have really got things the wrong way round when it comes to recruiting forwards,
Rather than starting with a clear idea of their system and picking players who suit it, Barcelona opt for the excitement of marquee signings, expecting them to absorb the 'Barca DNA' by osmosis later, and Griezmann was a particularly egregious example of this shortsighted approach.
Barcelona had all the money in the world last summer to really perfect the three-pronged attack of their 4-3-3, requiring a lightning-fast dribbler who could stretch defences on the left, and a hard-working striker who was fantastic off the ball and crucially, who had experience playing as his team's main striker.
Griezmann was none of those things.
Instead, Barcelona signed a player who is good at playing on the right and drifting behind the striker centrally - just like the greatest player of all time who he would shortly be playing alongside.
In comparison to Atlético's approach, which is contingent on good scouting and a little bit of luck, but fundamentally keeps the team's structure in place, Barcelona subsequently create a bigger problem for themselves by signing a player whose €120m price tag means he has to play, but whose awkward fit destroys the balance of the team.
When Griezmann plays on the left, his relatively poor dribbling fails to create any penetration for Barcelona, and up top he is isolated without any support - the fact that Martin Braithwaite, a far inferior player, no disrespect intended, has looked more comfortable centrally tells you all you need to know about how players lose out by being shoehorned into a philosophy, rather than being signed on the basis of their tactical suitability.
Atlético can afford to make one or two underwhelming signings so long as they retain their continuity - even the smartest clubs at their financial level don't recruit perfectly, with Mahmoud Dahoud at Borussia Dortmund or Xherdan Shaqiri at Liverpool springing to mind.
But for Barcelona it puts them another step behind domestic and continental rivals like Real Madrid, Man City and Bayern who aren't wasting time trying to accomodate square pegs in round holes, and won't be wasting more time attempting to make up for their mistake in protracted negotiations for Martinez or Neymar this summer.
If Barcelona have money, Atlético have sense, and it takes the two in tandem to build a truly elite side.