Polnareff just neeps on suffering through the series, sister gets killed, goes full revenge mode for years in order to try and find whoever killed her, gets controlled by Dio, thinks Avdol died because of him, the whole fake Avdol and sister deal on the island, thinks he scored a hottie but nope, licks a super dirty toilet seat, finds a nice lady but can't tell her who he was to not get involved in the mess even further, and now gets saved again by Avdol and this time he really dies.

It's not that he's selfish, so much as it is he's very caring of others to a fault which when combine with his very emotional personality tends to cloud his judgement. Plus Araki painted Polnareff as the comedic relief of the group so a lot of his more minor misfortunes are often by chance rather than his own shortcomings.