First off, close is a relative term... agree?
Second... guys that own (small business) engine/machine shops have a lot of "friends". They already work long hours, and most times when you see a closed sign in the window of the shop it's just to keep the "friends" out so they can work without interruption. At some point these engine builders realize that when they are giving out these great "friend" rates, they are actually not making that money, actually they are loosing money that they would otherwise be making. So, if your regular shop rate is $100/h and you are going to charge your buddy $60/h... you are not actually making $60/h, in reality you are loosing $40/h. See, your utilities have not changed, nor has your insurances business loan payments, mortgage etc etc... so, all you are doing by giving a "friend" rate is taking money away from yourself. You know what else happens, they end up not wanting to work on that project because it's literally costing them money, and now they are by human nature apt to rush through it...
Smart (small) business owners don't have "friend" rates. They have customers, and some of those customers are friends, who appreciate the quality of work and don't ask for "friend" rates.