How does Romeo and Juliet prove that significant relationships need quality time to develop?
I suppose you are infering through this question that the relationship between Romeo and Juliet was too sudden and because of its speed was not "significant." I have to disagree with this inference. I see no indication from the play that the depth of love between Romeo and Juliet was insignificant or that it would have been more significant had they taken more time to develop their relationship. I suppose one of the ways in which love is represented in this brilliant tragedy is that it can be something that comes upon us like a sickness and takes possession of us completely. Note the way in which Romeo, to use a cliched expression, falls in love at first sight:
Did my heart love till now? Forswear it, sight!
For I ne'er saw true beauty till this night.
Love is a force that often we don't have any control over, and which can overwhelm our senses and feelings. I see no evidence in this play to suggest that the relationship between Romeo and Juliet was not significant, nor to indicate that it would have been any more significant had they had more time to court and fall in love in a traditional manner.