Zacchaeus was a man with some authority, although despised authority. He wasn’t just a tax collector but a chief tax collector. And he must have been a bully and gang-banger because he was wealthy. I find this often among shorter people that they feel a need to prove themselves.
But Zacchaeus ran, short legs and all.
The people despised him because he was a “sinner.” But Jesus saw his heart. When presented with the Savior, Zacchaeus committed to give half his possessions away and pay back four times anything he had cheated. It was true repentance. People like Zacchaeus were why Jesus came. The crowds may not have seen him but Jesus sure did.