Some things in EQ happen with such stunning consistency that it baffles me.
As a necro I often like to group, but groups are sometimes hard to come by. So as a standby I'll throw LFG on then go solo somewhere till I get an invite. Invariably I will get an interested group the moment I arrive at some isolated spot. After making the run to Veksar (hiking through FV and LoIO has always been a bother to me) and making my way down to the Church...I get an invite to an EF LDoN. Which is where I had just come from to pick up my pet rune spell.
Another constant has to do with the Veteran rewards, but can be applied to any other activated ability with a long reuse timer. As soon as I use my double exp reward, without fail, I'll die on the next pull. This group I was in was very competent; we had done one adv in about 40 minutes with no hassles. So we went again. Since I was going to bed afterwards, and the exp was pretty crappy on its own I went ahead and used the Veteran reward. I was getting kind of warm so I took my sweater off. In the time it took to pull the sweater over my head, our tank pulled 2, got 3 adds and they all hit me at once. That ended up leading to a group wipe.
What other extremely annoying situation crops up every time it can?