In the Mos Eisley cantina, right when Luke sits down at the bar, Ponda Baba (who appears to be the companion of Doctor Evazan, the man with the mangled face) indicates his displeasure with Luke or something related to him, leading the man to confront him:
…I don't like you either. You watch yourself; we're wanted men…
Why does Evazan escalate this situation so quickly to outright threatening Luke's life? I can't imagine it would stem from anything Luke said (he tried his best to defuse the situation, but he was clearly a little uncomfortable with it). Obviously he was quite a hothead and maybe even a little bloodthirsty (how else do you have the death sentence in 12 systems), but did either being have a legitimate complaint?