I had a revelation one night last week.
I had installed GearScoreLite when Leesah first dinged 80. I wasn't in a guild at the time and I wanted to know my GS to see how close I was to being able to get into pug raids.
The GearScoreLite addon puts the target's GearScore in their tooltip and your own in your character window, that's all. It doesn't have any of the features that the full GearScore addon has, but all I wanted to know was what my GS was so the Lite version worked just fine for me.
Once I joined a guild it didn't matter so much, but I kept it out of voyeurish curiosity more than anything, to see what other people's gear was like without having to target and inspect them. I'd also kept it to see how Aefa's gear was coming along.
Last Wednesday in ICC, I managed to pick up Boots of the Frozen Seed. I was so happy becuase it was a major upgrade from the Boots of the Cracking Flame/Boots of Wintry Endurance I was wearing before. Since I was in Moonkin spec at the time, I realised I'd have to swap my nice cloak out for Kurisu's Indecision to stay hit-capped. With a sigh I said to myself, "Aw, that will make my gearscore lower again."
Then, I realised what I had just said, and gave myself a stern talking to.
"Now wait one cotton-picking minute there missy! That is not what you installed the GearScore addon for. You do not need to worry about that sort of thing anymore, only what is the best gear for your task!"
I realised that I had been looking at others and judging them on their GearScore, and that is really not why I wanted it at all. I had to remind myself of how angry I get when I see people on trade asking for a GS of 5k to do the weekly raid, and about the time when Aefa had been rejected from a VoA 25 for having a GS of 3000.
So I turned GearScoreLite off.
I've kept it on for Aefa for the time being, so I can keep telling pug leaders her score, but I need to train myself not to use it to judge people over their actual skill.
I don't want to open up a full-on GearScore debate here but I'd be interested to hear your thoughts on the use of GearScore as a raid building tool, or as a check on your own progress.