Dan
what i have found is some industry are harder to understand and most lenders that just go by bank deposits wind up having defaults in those industry . for example auto sales and not figuring in the floor plan .This problem i dont think you will have .
next is the industries people are scared of . legal , they can easily sue or fight contract . guns - they wind up on front page of news . collections - they know the default game and so forth .
next is the low margins and cant handle the payments / interest but this also good underwriting and pricing can fix .
lastly they are scared of the easy to close up shop , home based , drop shippers , etc.