Blunder number one occurred last week. I got a new set of hot pants. After the raid, I got an armor kit for them and gemed them with a good red choice and a good (new) purple choice. The two got me the set bonus of +6 agility. So, I was choosing to go with the set bonus at the loss of two agility for the gain of 12 stamina. 12 Stamina for Survival ends up being 13.1 Stamina and provides 3.96 AP to my pet and 3.96 RAP to me. So more RAP than if it was full Agility. More stamina for wiggle room. A tiny tiny amount less crit and dodge. Sounds fine. Ideal even!
I didn't notice that I had nuked my helm's meta gem requirements. So I fixed that up after our Tuesday raid. I probably also didn't notice it Tuesday because I was master looter running our DKP (Ni Karma) system for the raid. Heck! I didn't even notice I was still wearing my high item level set when I ran over to Razorscale after master looting FL.
So that leads into blunder number two. At least as far as gems go. I still have not one, but two Balanced Twilight Opals slotted. One in my helm and one in my neck piece. These had been the good option in some circumstances. Back.. oh before 3.1. But since 3.1 there has been a much better choice: the Shifting Twilight Opal. So, I need to get a few of those gems cut.
I could do a huge write-up of gems and include pictures and mouse-overs and what-not. But really, there's a comprehensive text-based review and recommendation over at Elitist Jerks.