These are images to display the problems reported with counters and cabinets when placing along diagonal walls:
1. Corner counter pieces will not auto place on a diagonal.
http://i916.photobucket.com/albums/ad5/SFsimpics/Sims4/Building/diagcounters1_zps1fae2478.jpg
2. Corner cabinet pieces will not auto place on a diagonal.
http://i916.photobucket.com/albums/ad5/SFsimpics/Sims4/Building/diagcabinets1_zps37402782.jpg
3. Counter pieces don't display backing on diagonal walls with certain orientations.
http://i916.photobucket.com/albums/ad5/SFsimpics/Sims4/Building/diagcounters2_zps284f8d80.jpg
4. Cabinets won't automatically snap together on a diagonal.
http://i916.photobucket.com/albums/ad5/SFsimpics/Sims4/Building/diagcabinets2_zps3d0d2c55.jpg