Answer:
He thinks Romeo is there to insult his family because of the ongoing feud.
Explanation:
Tybalt is an explosive and easily angered character. Moreover, he cares deeply about his family's honor. Therefore, he is immediately upset when he realizes Romeo is at the party. He knows that his family and Romeo's family are enemies, and therefore, he assumes that Romeo is there in order to insult the family. However, he is unable to attack Romeo because of the intervention of Capulet.
<span>Superstitious people might do many odd things because they believe in luck, or bad luck. So, they may retrace their steps if a black cat crosses their path, they may not want to walk under a ladder because it is sad to bring bad luck, they may be scared when their mirror cracks because it is believed to bring 7 years of bad luck. They may do many things to get out of a possible bad situation, or induce a good thing to happen to them.</span>