Mars, you tease.
You lure us in with your luscious auburn hue and your marble exterior. You even streaked your hair with dark green, Mars, just to drive Earth crazy. You tempt us with your promise of water, yet you remain just out of reach. That color! That shape! Cannot resist! Must go to Mars!
For your sake, Mars, I hope you continue to play hard-to-get. You don't want to tie yourself to Earth. Earth can't handle you.
Look at it this way: Earth is that handsome boy from high school who, by the age of thirty (million) has really let himself go. He's got the potential but he's run-down, he's sort of dirty, and just being in the same orbit as him makes you feel a little bit sleazy. Sure, he's nice enough, but give him a couple (thousand) more years, Mars. Make him clean up and get a job and maybe lose a little weight.
Mars, you are one classy gal. Like I said, you have a lot going for you - you're gorgeous, you're clean, you're pretty darn self-sufficient. Okay, maybe your life can get a little dull (no one really comes to visit you, after all), but the point is, you are in a great position. You have the universe at your, er, fingertips. You can do whatever you want. Don't let Earth come and get you all dirtied up.
Seriously, you don't want Earth visiting you right now. He's already sent you robots and crap, and just left them on you. Imagine if he himself went over there! He'd literally pollute you. And then you'd find yourself in an intergalactic raging drug war just to get more money to strike up a friendship with a third planet so you can dump some of your excess crap on them. It'll catch up to you eventually, Mars.
After Earth has gotten himself back in shape - after he's learned how to recycle and stop releasing all that gas - maybe you can let him visit you. But until then, you need to remain your cool and aloof self. Don't let Earth screw you over, Mars.
A Concerned Earth Resident
P.S. Regarding the title: Mars, I hope you still accept Pluto as a planet. As Dr Seuss once said, "A person's a person no matter how small." Don't discriminate, Mars.