the thing is, I accidentaly click that hide group check box, when i realize what wrong i try to find the group names or the manga name to undo the check.
that makes me want to review what if there another groups that i have accidentaly hides, and if there is, i want unhide it.
I too agree that a blacklist and/or 'finished list' would be a lifesaver!
It would save me so much time on the updates page scrolling through hundreds of mangas that I don't ever want to read or have finished reading, having to see them again and again is such a waste of both my time and Baka Update's bandwidth.