Between tons of inexplicable reasons, being a living proof that international breaks are too short (as some of them can and do play well in clubs, where they train with other players all the time and they know what other people will do, but in the national team they act like they are playing football for the first time all the time), having a mentality of a gelatinous cube under the hot shower (unless your gelatine has some chemicals that makes it not completely melt down under (hot) water, in this case gelatinous cube is better), and even more problems, a lot of things have happened.
You know how you call up the best players from your nation to try to make the best playing team and get the good results? It turns out that because the polandball is real representation of Poland, which is really upside-down, if you call up the best players, they actually turn out to play the shittest football possible, because they “nerf” each other’s abilities.