Tybalt is inconsiderate because he wanted to oust Romeo from Capulet’s ball, and he killed Mercutio.
Tybalt has a fiery temper, and can generally be described as inconsiderate. An inconsiderate person would be someone who does not take someone’s personal feelings into consideration. Tybalt seems selfish, so inconsiderate would describe him.
At Capulet’s ball, Tybalt gets upset because Romeo is there. Romeo is a Montague, and Tybalt subscribes to the family feud whole-heartedly. Even though the ball is Capulet’s, Tybalt wants to make a scene and kick Romeo out.
It fits when such a villain is a guest.
I'll not endure him. (Act 1, Scene 5)
Capulet is annoyed, and calls Tybalt a “saucy boy.” He does not want his guests to be disturbed, and considers it disrespectful of Tybalt to tell him what to do with the guests at his own party. He tells Tybalt to back off, and let Romeo be.
Tybalt also shows a lack of consideration in the brawl with Mercutio. He is still annoyed at Romeo for showing up at the party, and wants to brawl with him. This is highly inconsiderate, because Romeo is not doing anything. He calls Romeo a villain, and even after Romeo says he has no interest in fighting him, Tybalt does not back down.
Tybalt, the reason that I have to love thee
Doth much excuse the appertaining rage
To such a greeting. Villain am I none.
Therefore farewell. I see thou knowest me not.
Boy, this shall not excuse the injuries(65)
That thou hast done me; therefore turn and draw. (Act 3, Scene 1)
It is this lack of consideration, and Tybalt not listening at all to what Romeo is saying, that causes him to kill Mercutio. This causes Tybalt’s own death, which leads to Romeo’s banishment, and later his death and Juliet’s death. So really, Tybalt’s lack of consideration and his fiery temper really moved the plot along and caused the great tragedy of the play!