I had Mark in a few years ago to install a furnace. I recently had a home inspection, in preparation for selling the house, which discovered the humidifier was non-operational and the unit had never been grounded properly, causing potential danger of electric shock. I called Mark back in, and paid him to complete the work. No word of apology or acknowledgement from that this work was missed when the unit was originally installed.
A couple nights later, on the eve of the open house, I discovered part of the "repaired" humidifier was cracked and had leaked all over the floor. I was up late into the night cleaning the water, installing fans and dehumidifiers, trying to dry it all out.
Once the house sold, I told Mark what had happen, and asked him to come back. Instead of taking any responsibility, he defaulted to explaining how this wasn't his fault, and he would have to be paid again to complete the work. I was annoyed, but because I'm busy, I offered to pay him $100 to rectify the situation. He said the cracked part alone costs that amount.
I sourced the part online for $6, and will have someone else install it. I do not like working with contractors who won't take responsibility for their work.