When a young family with two small children were awakened by a banging noise coming from our furnace at 6:00 am, needless to say they were not happy. The banging would stop then start again after about 15 minutes then repeat the cycle of banging every 15 minutes. On top of that, we did not receive their calls or texts for a couple of hours.
We felt so badly about this experience, that we had a small lego set, a stuffed animal and flowers to present to them when we said we would be over to fix the problem immediately. The gifts did not cost very much and to us, it was the least we could do for such an inconvience. The guests said it was not necessary, but they also felt it was a great jesture and all was forgiven so to speak. They were not happy initially, but the gifts meant alot to them.
Saying all this, buy little gifts or tokens when in the store on sale and keep them on hand for such emergencies. A few dollars spent on these items go a long way to making peace and shows the guest that they are important to you as their host. We have games, toys, little travel perfume, soaps, etc. on hand just for our guests if and when we have household problems, even though most or all are beyond our control.
Also, if a big group stays in our home or a long term stay, we always have fresh flowers in the dining room and their bedroom when they arrive. We feel that is the least we can do to show our appreciation. Additionally, I read a Harvard Medical School psychologist found that women who saw flowers when they woke up reported feeling happier and less anxious at home, as well as more energetic at work.