The short and simple explanation of why the FSO Polonez was such a bad car is that is was a produce of Communist-era Poland. This explanation in itself, however, is possibly not enough. After all, Lada and Skoda were also both communist-era cars and, while they were certainly bad, neither was as bad as the FSO Polonez, which was indisputably one of the worst cars ever to disgrace the UK's roads. Here are three reasons why.
Whoever chose the name FSO Polonez hopefully had a well-developed sense of irony. The "Polonez" bit not only reflected the car's country of origin, but was also a homonym with the word Polonaise, which was (and is) a very elegant and graceful dance, which was often used to open major ceremonial occasions. The FSO Polonez, however, was very definitely one of the ugliest and clumsiest cars on the road. This is in spite of the design for its body having been put together by no less a pairing than Giorgetto Giugiaro (named Car Designer of the Century in 1999 and inducted into the Automotive Hall of Fame in 2002) and Walter De Silva (who went on to be head of Volkswagen Group Design, only retiring in 2015). Even the best, it would appear, could get it wrong, very wrong. The exterior alone was enough to see the FSO Polonez routinely ridiculed in the automotive press, which could hardly have made it more appealing to own one.
The FSO Polonez had a very long body, which meant it was actually quite big for its time, but in the early days it still used the same 1.3L and 1.5L engines as its predecessor the FSO Polski Fiat 125p (albeit with a few minor changes). This meant that it simply didn't have the raw horsepower to impress on long, flat stretches such as motorways. As production continued (the FSO Polonez was produced between 1978 and 2002), the specifications did begin to improve, with FSO turning to Fiat, Ford Peugeot and Rover for better engines, but the hard fact of the matter was that FSO was always behind the motoring curve in pretty much every way.
According to FSO, crash tests showed that the FSO Polonez was actually very robust in crash situations. According to the public at large, it was a liability to drive. Possibly the reason for this contradiction is that the overly-long body together with the car's notoriously poor handling may have made the car more prone to accidents than your average motor, which, understandably, didn't do it any favours in the eyes of the motoring public, even if that had confidence in the crash tests which "proved it safe". It didn't take long for the FSO Polonez to develop a reputation as an accident waiting to happen, which, again, was hardly a great incentive to buy one if you could afford something, anything, better, which was practically any other car on the market.