Actually, it does suck: the system is biased towards the married.
Don't forget the brat kids.
And it shouldn't.
I'm sure I'm on every married parents "Must Kill Now" list, but tax advantages for having a marriage certificate and/or having children are counterintuitive.
Otherwise, two people buy a hot dog. @Autothrust Blue pays 8.25% sales tax, I pay 6% because I'm married and @scooter2525 pays 4.5% because he's both married with children.