OOOOHHHH I absolutely know what you mean …. i was looking for the “last” bauble in zone 2 for over 1 hour (by using a guide) and was absolutely sure that i got them all. But I didnt get an achievement. So i kept looking …
I didnt know that I have to kill the boss to get it! >_< Would have saved me 90 minutes if i knew it before ….
And yeah, a counter would really help if you want to find them on your own. If you use a step by step guide like me i dont think its necessary ^^"