(Keep this in mind before you read: Doctor Manhattan is a genius who has just logically proven that all life is meaningless and just afterward, Laurie discovers that the man that she hates the most is actually her father. As a result of the truth about her father and Doctor Manhattan discourse one the meaninglessness of life, Laurie is weeping and distraught. It is here that the amazing dialogue between Laurie and 2 begins)

Laurie: My whole life's a joke. One big, stupid, meaningless... aw crap...

Doctor Manhattan: I don't think your life's meaningless.

Laurie: Oh no, well, obviously that's what you're going to say because anything I'm stupid enough to believe is true, you just disagree with it and... uh... you don't?

Doctor Manhattan: No.

Laurie: But... listen, you've been saying life is meaningless so how can...?

Doctor Manhattan: I changed my mind.

Laurie: But... why?

Doctor Manhattan: Thermodynamic miracles... events with odds against so astronomical, they're effectively impossible, like oxygen spontaneously becoming gold. I long to observe such a thing. And yet, in each human coupling, a thousand million sperm vie for a single egg. Multiply those odd by countless generations, against the odds of you of your ancestors being alive; meeting; siring this precise son; that exact daughter... until your mother loves a man she has every reason to hate, and of that union, of the thousand million children competing for fertilization, it was you, only you, that emerged. To distill so specific a form from that chaos of improbability like turning air to gold... That is the crowning unlikelihood. The thermodynamic miracle.

Laurie: But... if me, my birth, if that's a thermodynamic miracle... I mean, you could say that about anybody in the world!"

Doctor Manhattan: Yes. Anybody in the world... but the world is so full of people, so crowded with these miracles that they become commonplace and we forget... I forget. We gaze continually at the world and it grows dull in our perceptions. Yet seen from another's vantage point, as if new, it may still take the breath away. Come... dry your eyes, for you are life, rarer than a quark and unpredictable beyond the dreams of Heisenberg; the clay in which the forces that shape all things leave their fingerprints most clearly. Dry your eyes... and lets go home.

"To say 'love is like a rose' is a foolish and shallow statement...but why you may ask; well, there's a lot of reasons:
i mean, roses only last like a couple weeks, and that's if you leave them in water, and they really only exist to be pretty. So that's like saying "my love for you is transitory and based solely on your appearance".....................
But a potato! Potatos last forever man! In fact, not only will they not rot, they actually grow stuff even if you just leave them in the sack; that part alone makes it a good symbol. But there's more, there are so many ways to enjoy a potato! You can even make a battery with it, and that's like saying "i have many ways in which I show my love for you" and potatos may be ugly, but they're still awesome
so that's like saying "it doesn't matter at all what you look like, I'll still love you"