Thought it was time to update the GS list with some new observations...

GS0 - Entry level provisional GS - typically via a short term challenge or mid year upgrade from 1K.
GS1 - Typically corporate gifts - CEO's / Presidents get these from contracts, mostly looked down on internally and at the lounges
GS2 - Known internally as "GS Lite" - barely qualified / first year provisional member - corporate hopes to move these up the ladder
GS3 - The "Road Warrior" GS - but not really HVF but spend so much need to keep loyal
GS4 - Standard GS HVF - mostly premium international flights
GS5 - The Exceptional GS level - possibly qualifying for Chairmans Circle - mostly worshipped by lounge teams.
GSK - The Kardashian level GS - spends a reckless amount of money, never uses upgrades, keeps coming back in spite of service level issues – knows it could be better but doesn’t care. After a brief upgrade, I am back to this level...
GSC – Global Services via corporate designation. Often found on APAC flights from NorCal. Often don’t even know what Global Services is or what it means. Many reports of Apple employees at this level, but in reality multiple companies are able to designate. Frequently confuse “Global Services” with “Global Entry” thus creating more anti-GS fodder in US immigration halls across the US.
GSE - this special breed of GS flies out of Newark. Highly experienced travellers that have spent a lot of time in the airport - they know all the right places to be - including that drinks are served in the United Club A terminal 2 hours before the C terminal. They are highly aggressive - and have to be. It is easy to spot this GS at other airports as they compulsively walk only at the extreme edges of the terminal and do not like to be in any open spaces. They also do not like to interact with humans when ordering any food or drink.
GSL - LAXOGG - Fly a ton, sets records for speed to achieve 1MM (10 months). Very well-known but always presents a low key presence - welcomed to lounges with a knowing grin as a 4MM member - and you would never know as it's not worn as a badge of honor
GSU - UA1Flyer - The "Elvis" level - true Rockstar celebration, including pictures, at most lounges and on the plane. Spends more time in air than on ground. Fantastic advocate of and for UA - never discuss automobiles with this level or that he travels with other companions...
GSW - GS WannaBe. Premier member who just keeps missing or former GS that can’t accept life without GS status. Often caught trying to sneak in behind GS pre-boarders or at the GFL.
GSS - GS Spouse (and let's everyone within earshot know it). Do. Not. Cross. Frequently plays the DYKWMSI card while ordering their 5th PDB talking on the phone to their interior designer.
GSM – A special level of GS4/5 that receives Mercedes pick up service and boards directly from the tarmac via the stairs on the jet-bridge. Not available to GSK level who must run between terminals - especially in IAD/ORD - and EWR when arriving in terminal A.
GSI - ILuv2Fly level - Hub-captive GS level, Obsessed with detail but down to earth - Similar to GSK level spend but eat at White Castle regularly thus endearing themselves to lounge staff and forum members globally
GSP - Special level reserved for newly minted lifetime GS (4MM miles). Has achieved everything possible but seemingly covets more... This rare breed of GS can often be spotted mowing down the disabled and children in pre-boarding and then BG1 on their way to claim their righteous place during boarding after arriving via Mercedes Benz. Always attempt to move with the swagger of John Travolta in Saturday Night Fever but in reality appears more like Will Ferrell as Ricky Bobby.... There are only two future options for this level GS - they can grow wise and patient with proper perspective like ua1flyer, or end up in the asylum refreshing FT pages endlessly.... Do not confuse with GSL level...
GST - The "Truculent Glare" / Medusa / Dirty Harry Level. This level GS is known for their amazing ability to instill fear and intimidation in even the most aggressive UA employees including the famed GFL lounge dragons. Refuses to take no for an answer. When challenged they tilt their head slightly and employ "the knowing look" - as in "you mess with me I will make sure your next job is deicing planes in Anchorage" and then asks a simple question - "So, do you feel lucky?" Typically an experienced flyer who relaxes by memorizing SHARES codes and knows the UA rulebook better than UA employees. Wears such knowledge as a badge and wields it as a weapon. Has memorized all GG codes.