How can you tell if a relationship is serious?

She sat amongst my team of barflies and bravely poked me with a stick.

"What's your story, Phil?"
"I'm happily single. You?"
"Single too. When was your last serious relationship?"
"Serious from whose perspective?"
"Huh?"
"Serious from the perspective of women I've dated? Your perspective? Mine?"
"You know what I mean."
"Not really."

I had to explain to Nelly the subjectivity of her question. I gave her examples. On a scale of one to five, five being most serious, here's my belief:

• Having this discussion: 1
• One-night stand, never saw each other again: 1.5
• Three dates without penetration:1.5
• I cook her dinner: 1.5
• She cooks me dinner: 2
• She watches me play baseball: 2
• I encourage her from the sidelines of a marathon or other event: 2.5
• I meet her family: 2.5
• We vacation together: 3
• She meets my family: 3
• We have double-dates with her friends: 3
• We bring each other around coworkers: 3
  
• We simultaneously brush teeth in adjoining sinks: 3
• We fart or pee in front of each other: 3.5
• I walk her dog: 3.5
  
• She spends an entire weekend at my house: 4
• We agree to each have blood tests done to avoid those pesky condoms: 4
• I hold her hair while she pukes: 4.5
• Her pet spends an entire weekend at my house: 4.5 (unless it's a sea-monkey)
• My bathroom contains her toothbrush (2), girlie soap (2.5), facial cream (3), makeup remover (3.5), tampons (4), underwear (4.5), or vibrator (5).
• Her bathroom contains anything of mine, other than toilet rim pee spots and hair: 4.5
• She gave up the butt: 4.5
• I gave up the butt: N/A (because it's not gonna fucking happen)

I'm strongly considering laminating and inserting this list within restaurant menus. Much is lost in subjectivity. Rarely do I find someone--especially one with ovaries--who agrees with my definition of "serious."

Alas, my honesty and sarcasm left the lady unimpressed, unreceptive, and unmatable. So be she.