Romeo's flaw was that he would not think before he would act. He would fall in love way too fast such as when he first saw Juliet and kissed her shortly after. "Then move not while my prayers' effect I take. Thus from my lips, by thine my sin is purged. (kisses her)." (1.5,203,91-108)
Moment of Critical Discovery
This is all my fault!!!
Romeos action of marrying Juliet after a short while after knowing her and knowing the common sense consequence, it is what caused everything bad to happen. Clearly his pride got the best of him in which they both paid for. "Ah, Juliet if you're as happy as I am, and you're better with words, tell me about the happiness you imagine we'll have in our marriage." (2.6.2)
Fate Worse than he Deserves
Tybalt kills Mercutio which leads to Romeo going out in rage and mixed emotions. While feeling those things, Romeo kills Tybalt out of revenge. "This shall determine that." (3.1.115-128)
Pity for Tragic Hero
Romeo finally realizes that he is the cause of all these horrible events that have happened. "Thou canst not speak of that thou dost not feel...." (3.1.57-70)
Since Romeo wasn't confirmed that her "death" was just a trick, he goes out, buys poison, and kills himself next to Juliet. "Thy drugs are quick. Thus with a kiss I die." (5.3.74-120)
I love you Juliet......
The two families realized what their feud did to their children so they put an end to their fighting and became friends. Capulet: "Oh brother Montague, give me thy hand. this is my daughters jointure, for no more can I demand." (5.3.296-310)