Understandable..But this isn't his job, he probably was only doing it as a favor. Maybe you should talk to him before assuming that he was just lazy?
Maybe I am biased, but I know first hand how hard it is to work at a barn. I don't know how many horses you have but at mine we have 20+ and I have to pick all the stalls, give new bedding, feed & water them, turn them all out, sweep the lonngg hallway, and work with a few horses. Sometimes it's hard to pay attention to every little detail. I bet it was especially hard for him because he doesn't work there everyday and he doesn't know the horses and he doesn't know what the owners want.
I was once yelled at by a boarder because her horse was on stall rest and I picked out the horses stall, while picking I tied the horse up in the stall because she was always so nervous and was always swinging her back end towards me. Anyway, long story short I untied the horse and I left to go work on the other stalls, but guess what? I left the horse's halter on. I got an ass chewing and all I wanted to say to her was, "lady you have NO idea. You should wake your a!s up at 5:30 until 3:30 everyday. Then once you do that you should come back and yell at me. Step into my shoes." But of course I couldn't because the boarder is always right so I batted my eye lashes and told her, "I'm so sorry it will never happen again." It never did happen again, because I learned. Sometimes that's all it takes, is to just get yelled at.
I always try to get all the stalls and things done before any of the owners get out of work and come, lord knows one of them will come and something won't be right or perfect enough. But when you're trying to get all the things done for the BO sometimes you don't have time to take and stare at every chart on the stall door. I know the first couple weeks it was so hard, now I have every horse down and I know what they need/don't need. But for a guy who doesn't work there regularly it's not going to be perfect.