I had someone in yesterday to complete work in my house. I was in another room and left him to it, but he kept swearing and cursing throughout the job. He wasn't rude to me or anything, I don't know if the job was harder than he thought but he didn't mention anything, he completed it quite fast.
He just kept shouting 'fucking hell!' And 'for fucks sake!'.
It made me a bit uncomfortable, he was a young lad around early 20s I think and was sent by his boss, what would you have thought?