I'm landscaping a yard for an old time family friend. Fully legitimate business deal, went through an estimate, a contract, deposit, the whole nine yards. So my friend's neighbor that lives behind her is also a landscaper. She had asked him and myself to do an estimate for her. Her neighbor never did, but I did and got the job. I've started the project, cutting all the weeds down, put loam down. Everytime I'm over there, I'm almost guaranteed a call that evening. The call is something about how, "Her landscaper neighbor says you didn't do enough of this, or didn't do this properly, or need to do this, etc." And she always tells him that I know what I'm doing, ie: she backs me up, she has confidence in me. I've only run into the landscaper neighbor once, and it was just him staring at me shaking his head, but I feel like the next time he might start in with his "suggestions." I have neighbors of mine who don't use me to landscape their properties--which is fine--and I have never gone to my neighbors and begun questioning their landscaper's techiniques. I just feel that's unprofessional, and a bit immature too. How do I handle any potential confrontation that I might have with this guy? I obviously have to work there, so I can't just walk away.