Whether it be in terms of whether they didn’t play as well as you expected them to be, or if they were injured/unfit all the time during their career at your club or perhaps got on bad terms quickly into their career at your club (e.g. Di Maria at Man Utd).
As a Liverpool fan, I can think of names like Aquilani, Robbie Keane, Morientes, Andy Carroll, Kewell, Litmanen, Nuri Sahin etc.
But the one that has to take the cake is Naby Keita. I was very excited when it was announced he would be joining us. He was like the 2nd best midfielder in the Bundesliga that season for Leipzig in the data and for a couple of seasons had shown a lot of great technical ability. He joins us and the rest is history. It’s not to say he didn’t have good moments with us when he had a run of games in the first team. But that was presicely the issue, getting a run of games. It was a constant cycle of spending over half his time injured and when returning, not always having his best games due to slowly returning to fitness and when he did start showing his sparkle he’d go off injured again for a while. I am not just gutted for us but gutted for him too in how it could’ve and should’ve turned out.
For arsenal I think Lacazette was the worse High to low. We were pissed that we got welbeck and laca scored 5 in a game in France.
When we signed him he looked to be clinical. But soon 6 months later we got a WC striker in Auba and laca didnt pan out especially since we lost Giroud.
Pepe was over priced but didnt tank as much as people percieve it. He had quality and end product. The whole squad was shitty at the time when i think back and he would probably a similar level of sucecess to Leo if he came into this side.
There was shady dealings with the agent, I hope they are investigated.