One trait that Romeo, Juliet, and Friar Lawrence all have in common is that they are all romantics. They want to end the feud that plagues Verona. They all believe in true love, and want the world to be a better place.
Romeo clearly does not support the feud. When he sees the aftermath of the duel in Act 1, he is saddened.
O me! What fray was here?
Yet tell me not, for I have heard it all.
Here's much to do with hate, but more with love. (Act 1, Scene 1, p. 16)
Romeo and Juliet are the young lovers at the center of the story, but Friar Lawrence plays a pivotal role. He agrees to marry them, because he hopes it will end the feud.
It underscores Romeo’s romantic nature that he is concerned about the duels. Most people seem to just accept it, are heartily take part in it.
While Juliet is also at the heart of the feud, she throws off her hatred readily enough when she meets Romeo. She really does not care that he is a member of the family her family is warring.
My only love, sprung from my only hate!
Too early seen unknown, and known too late!
Prodigious birth of love it is to me
That I must love a loathed enemy.(150) (Act 1, Scene 5, p. 34)
Juliet eventually decides that a name does not matter, because she loves Romeo. She wants to marry him anyway. She wishes the feud would end.
Obviously, the fates of these three are closely intertwined, and Romeo and Juliet are not the only romantics.
In one respect I'll thy assistant be;
For this alliance may so happy prove
To turn your households’ rancour to pure love.(95) (Act 2, Scene 3, p. 47)
As Romeo’s advisor, Friar Lawrence also serves to advise Juliet. When Romeo is banished, she comes to him to find a way to avoid marrying Paris. He gives her a potion to fake her death. He has no idea it will end up starting a chain of events that ends in both lovers’ suicides. However, the feud does end.