Q1. Happy: Last scene in Christmas and Jackie's "I love you" scene. Sad: Jackie Bags Hyde, the end of YSM, NFBM, and the skank scene in The Kids Are Alright.
Q2. Never had a boyfriend. No dates. Ever. No action. Ever. I'd take a Hyde.
Q3. Including the ones that implied that they were in a car together, though unseen:
That '70s Pilot
That Disco Episode
Ski Trip
That Wrestling Show
Prom Night
Water Tower
Hyde Moves In
Halloween
Vanstock
Kelso's Serenade
Jackie Bags Hyde
Dine & Dash
Eric's Depression
Pinciotti Vs. Foreman
An Eric Foreman Christmas
Tornado Prom
Hot Dog
The Crunge
Misty Mountain Hop
Babe, I'm Gonna Leave You
The Battle of Evermore
Hey, Hey, What Can I Do?
Trampled Under Foot
Nobody's Fault But Mine
Celebration Day
The Acid Queen
Christmas
I'm A Boy
Won't Get Fooled Again
Man With Money
My Wife
Going Mobile
The Seeker
I...
think I counted 33. Edit: Yep, 33.