I'm just annoyed by the regions issues, you'll get pretty biased results depending in what region you select.
If you try to search for something specific to a region with other selected you'll find sometime empty results, which shows you won't get relevant results about a search if you don't properly select the region.

Probably this is more obvious with non technical searches, for example my default region is canada-en and if I try "instituto nacional electoral" I only get a wiki page, an international site and some other random sites with no news, only when I change the region I get the official page ine.mx and news. For me this means kagi hides results from other regions instead of just boosting the selected region's ones.