I read about the concept of the emotional bank account years ago in a great book called the 7 Habits of Highly Effective People (by Stephen Covey). It used a bank account as an example to make a correlation between deposits and withdrawls of money and building strong relationships. Like you might imagine it can take many small deposits to build trust, and one large withdrawal, such as lying, could empty the account quickly.
I found this to be intimately true in business relationships. You need to be making constant deposits. Helping your clients when it has no benefit to you, taking a genuine interest in there success and happiness. Then when mistakes happen (and they do) you will make a withdrawl, but you should have plenty of reserves to maintain the relationship. If you treat your clients like transactions, and live your emotional bank account paycheck to paycheck, you are one mistep from having your clients find a better invested option.