The IRS is always your adversary, but the people who write the tax code become your friends at a certain point.
the IRS simply does far more than enforcement, at a certain point it switches from hiding from the IRS, to filing and hoping you arent picked for scrutiny, to informing the IRS ways you wont pay them taxes (ie. 83b elections, S-corp designation, 5500 for tax deferred plans), to collaborating with the IRS on not paying taxes (ie. 501(c)X non-profit approval, Advance Pricing Agreements)
The passionate overzealous people in the audits and enforcement division are just one part of the IRS, thats my point
There are some very obscure areas of the IRS with pleasant people just waiting for attention to help you with a less used part of the tax code