It wants taxpayers to be afraid. Voluntary compliance, though fragile, is the major support of our tax system. There are those inside the IRS who think it is their mission to make people afraid of them, believing the more people are afraid, the more they'll comply with the tax laws. IRS auditors won't go out of their way to dispel taxpayers' notions about their image. You will find them courteous and polite, but don't expect them to be friendly.
First names are a no-no, and so are lunches and dinner.
Bringing flowers with you to the audit will not enhance your image. Instead it will cast suspicions upon your motives, and result in a more vigorous audit. Remember that IRS employees are basically suspicious individuals. They don't trust anyone, not even co-workers, so they could hardly be expected to trust taxpayers, particularly those being audited. Forget all the business techniques you've learned about social communication skills.