Always bear in mind that you are the employer and she is the employee. You treat her good because she's a good helper, don't expect any reward or appreciation from her. She will take it for granted if you are too good to her.
Absolutely agreed with you. Employer-employee relationship. Nothing more than that.We should never try to make them part of the family, because they are not! Treat them with normal respect and that's it. We pay them to work for us. We have the right to expect them to follow our instructions. We have no responsibility to please them.
Always keep a distance. Be reasonable but no need to be overly nice, not necessary and may invite troubles.