If getting stuff online is cheaper, why do I visit you?
Service, stoopid. I am going in because I have a question about something that I am not sure I can do myself, or because I want something done right the first time around and it would take me more time than I care to spend on it myself.
I don't want to ask for something to be done a certain way (like change my chainring and put a new chain with one of those easy to break links but DON'T break my old chain because it has one of those links too), to find out that your mechanic went ahead and did whatever he wanted (like break my old chain in the wrong link and install the new chain WITHOUT the easy release link).
I also care about safety. There are certain things I can do myself but I ask a specialist to do because I do not want to find myself at eye level with the tarmac because something went terribly wrong. For instance, I do not want to notice that my wheel is so far forward on my dropout that only about half or 2/3 of the nut is biting into the metal. If I ask you about axle creep and the possibility that the whole thing might just fall off, don't tell me that it does not happen and justify it by saying that you have been a mechanic for 14 years and that it does not happen. It is bad customer service and it makes you look stupid when all it takes is a google search to show you that it does happen.
I also go in because there are some parts and tools I don't have. So when I ask you if a half link would not be a better idea than leaving my axle hanging on or dear life from my dropout (my dear life, as it happens), and your shop specializes in fixies (a lot o which are conversions like mine) I kinda expect you to have it. It is ok if you don't, but you see, now I think that the reason why you left my axle in such a precarious position and then told me with a straight face that axle creep does not happen is because you did not have a half link to do the job properly in the first place but making a sale was more important to you than doing something right.
The upshot is that I am spending some time to undo the hack job your mechanic did, putting my old chain and chainring back and ordering that half link you did not have from an online bike shop.
So, dear LBS, I do hope you don't mind my not coming back. Come and think of it, Brick Lane is not even that local to me. I had heard from others that it was a bad shop, but I had no complaints myself. That was before my perfectly safe bike was put in a state where I am not comfortable riding it.