Shishupal hated Krishna?

Shishupala hated Krishna enough to commit a hundred sins and then get killed by him. But why so? What did Krishna do that Shishupala started to hate him that much??

Shishupala wanted to marry Rukmini, the princess of Vidarbha and so did her brother Rukmi. Unfortunately, Rukmini had already fallen in love and dedicated herself to Krishna on hearing stories of his valour and wit. So, Rukmini wrote a letter to Krishna asking him to 'kidnap'  her and marry her which Krishna did. Rukmi then challenged Krishna for a duel to try and stop Rukmini from leaving with Krishna which Krishna easily won. On the behest of Rukmini, he spared Rukmi's life and instead shaved of his hair which was a sign of defeat and shame for kshatriyas. 

Thus by eloping with Shishupala's intended and shaving off his best friend's hair, Krishna entered his bad books. Shishupala was already previously jealous of Krishna for he had lived his life as a shepherd and was now being referred to as a lord. This incident just made Shishupala hate Krishna more.