Hi I need help with creating a fishbone diagram. The problem is 'long queue at cashier' (in a grocery store). I am having trouble coming up more with categories and of these primary and secondary causes. It can be anything such as process, systems, method, material, etc.

I have done customer, staff, and equipment already. Can you make some other suggestions?

Customers Lack of training Staff No show Poor customer service skills Insufficient number of staff Complaints Poor work ethic Poor shift management Arrogant behavior Long queue at cashier Slow Outdated technology Equipment Eftpos machine broken