With Mayo and the Chevron standard in full force, will the IRS become bolder in its interpretation of Treasury Regulations? This question is difficult to answer because “there is no objective metric for measuring how good a rule is.” Adding to the existing problems, in recent years, the IRS has attempted to increase its enforcement efforts aimed at abusive tax shelters; however, these efforts may end up affecting honest taxpayers instead of the intended targets. Taxpayers should be concerned that the IRS will “adopt one-sided interpretations of the law favoring the government.” Maybe the IRS is the ideal agency, is completely rational, and does not give in to heuristics. However, as research shows, this is highly unlikely. Courts should be aware of biases and heuristics that accompany agency regulation and act as the proper check to its biases. While strong deference to the IRS might be effective in the short-run, the IRS may develop less incentive to check its own biases in the long-run without another branch of the U.S. Government—namely the Judiciary—acting as a check to its now vast regulatory powers.