Does this picture give you the creeps?
The inks in the three Esterbrooks above are, L-R, Namiki Blue, Noodler's La Reine Mauve, and Noodler's Black. The LRM is one of the nicer purples I've tried, but it's expensive, and all the pens I've tried it in end up with the nibs looking like this. The same pen had Lamy Blue in it before this, and the nib just had a couple of little ink spots. The only other ink I've tried which is close to this creepy is Kung Te-Cheng.
Wondering why certain inks are creepier in my pens than others, I found this article on Richard Binder's site. For those who haven't seen it, I think it's an interesting explanation of what is happening. Quick summary, it's not a defect in the ink, but the result of scratches and imperfections in my nibs. Certain inks just bring out these imperfections more than others.
I think I can live with a certain amount of creepiness, as long as I don't dump a lot of ink in the cap. I'll have to pay more attention, though, to which nibs are creepy, not just which inks.