Roller Coasters...Vis-à-Vis Relationship Psychology

Sometimes there's nothing more apt or consoling than a monstrous cliché. So, uh, life is like a roller coaster. I recently had to cover the history of Six Flags, and having logged time as a casting recruiter, I've scoured my share of theme parks looking for "hotties." All those hours spent in the spindly shadows of gigantic roller coasters got me curious about how they're built, maintained, disassembled, etc. One of my favorite rides at Magic Mountain--Flashback (née Z Force)--has been labelled SBNO (Standing But Not Operating) since 2003, but has since been disabled. Which got me thinking about what other diagnostic terms were common in the roller coaster world, and how those terms--in another context--might be misconstrued to apply to relationships. Fun with examples after the jump.

Standing But Not Operating

What it means in the roller coaster world: dormant coasters whose futures are vague due to any number of issues; however, they're still counted in inventories determining which parks have the most coasters.
Why it sounds like a relationship issue: let's be honest: everyone has a few lame ducks who bolster some anxious emotional inventory...
Anti-Rollback Device

What it means in the roller coaster world: it's the ratchet that makes the clicking noise as you're (slowly, excruciatingly) going up an incline; it'll save the day if there's ever a power failure or chain rupture--you won't be going anywhere.
Why it sounds like a relationship issue: anti-rollback devices can be people, surely, (they'll pick you up to go chanting or help you throw out items that've outgrown their sentimental value), but they can also be fierce new haircuts or a new set of locks: anything that prevents you from regressing.
First Drop

What it means in the roller coaster world: pretty much what it sounds like--the first major plummet on any given ride.
Why it sounds like a relationship issue: take your pick: it's any of those first minor blips that metastasize into a deal breaker.
Positive G's

What it means in the roller coaster world: when the gravitational forces exceed 1 G--usually on inversions & high speed turns, making it hard to clap your hands or make a facial expression.
Why it sounds like a relationship issue: anything they do that impairs your ability to properly respond (most likely this is a vice that comes across charming); at first, this talent/issue/thing of theirs makes you feel great (hence the positive), but ultimately it leaves you feeling weak and impacted.

Any you'd like to add? Or maybe actual names of roller coasters are more inspiring...