It's disturbing how much information customers process about your business and how quickly and "unfairly" they make their judgments about whether they want to do business with you. Without realizing it, over and over, your business is almost certainly driving away customers through subliminally off-putting factors that you're not even aware of.
Distinct from the central factors we more commonly focus on in business--pricing, marketing, distribution, product quality, and so forth--what I'm talking about here are negative factors so "picky" that customers would never feel comfortable bringing them to your attention and may not be consciously aware of themselves. Yet these turnoffs can make all the difference to your bottom line and to sustaining your success.
1. You smell funny. Factors that are only on the periphery of consciousness, including those senses that we rarely talk about in polite company, can affect whether a customer wants to continue to do business with you, including air temperature and quality (are you stifling or freezing your clients?) and even how your establishment smells. The offices of a corporate consulting client of mine once had an underlying mildew smell due to prior flooding. Although I noticed this the first time I met with them at their offices (hard to miss, really!), they were entirely oblivious to it. They had acclimated to the scent through daily exposure.
2. You look nasty. Dirty restrooms, neglected plants ("If they can't even take care of a plant, how will they take care of me?"), rudely worded or out of date signage, dead houseflies slowly mummifying in the fluorescent light enclosures of your drop ceiling.... (This last one is a real example from a dentist I consulted for: Her patients had a straight-on view of this icky scene every time their seat was locked into the "recline" position for treatment, while the dentist, of course, didn't know until I pointed it out to her. She was always looking in a different direction.)
3. You sound obnoxious. In almost every industry that I consult for, soundscape missteps are a frequently overlooked issue. This includes the foodservice industry: At an Asian fusion restaurant, for example, the first thing I noticed on my consulting assignment was that the radio used by the employees in the kitchen was competing with the carefully selected music at play in the dining room. At particular booths in the restaurant, it sounded like that dissonant Charles Ives piece where two bands are playing out of tune with each other. Something had to give, and, again, the restaurant personnel, not sitting in their own booths, didn't notice the auditory conflict.
4. You don't make customer entry easy, offline or on. If you're in a neighborhood with tight and competitive street parking, not only should your register be fully stocked with quarters for customers who need to feed the meter, you should be running out to the curb to insert the quarters yourself for arriving customers without them having to leave the car. How hard is your front door to open? It's a lousy first and last impression for a customer to have to struggle with a misadjusted door closer. (This is not just a comfort issue, by the way: Difficult-to-open doors generally violate the Americans with Disabilities Act, as do non-self-closing doors on restrooms. Think about that one, and the reason behind the regulation, and I think you'll understand.)
The same thing is true online: How easy is your public website to log in to and use, if in fact there's a need to log in in the first place?
5. You make your customers feel invisible. Service should begin when a customer makes visual contact with your employees; it shouldn't wait until the employee decides to make visual contact with the customer. In other words: When a customer enters your establishment, they'll notice your employees immediately. And if what they experience upon entry are your employees continuing their work or their chitchat with co-workers, and making the customer wait until the right time to "interrupt" the work in progress, the customer will feel unvalued and invisible. (Hat tip to @billquiseng on this one.)
The solution to these--and to many more--"peripheral" issues? Take a customer lens, a customer POV, to the situation. Don't park your car in a reserved employee spot--park it where customers are forced to park, and enter your business by the same entrance they use. Don't use your auto-login override on your computer; make yourself use the same login procedure you're forcing your customers to endure. To help you discover problem areas that you can't be expected to notice yourself due to your extreme familiarity with your own business (the unnoticed mildew example is a case of this) or where you can't really get the treatment that an anonymous customer would (the "being ignored upon entry" issue is an example of this) get a trusted co-conspirator to critically check you out as well.
One more master tip here: A lot of this stuff isn't exactly unnoticed by your employees. It's more likely noticed just once and then forgotten about. The solution to this phenomenon is to deploy a company-wide continuous improvement system, where every employee not only can but is required to make a note of defects that come to their attention, notes that are followed up in a systematic manner. This is infinitely better than letting these subtle issues fall through the cracks, and risking that your customers' loyalty will fall through the cracks as well.