Not only was he interfering in the Stone prosecution and sentencing, but it appears he forced career staff at DOJ to:

-- Investigate mergers of cannabis companies under antitrust laws not because there was any antitrust basis for the investigation (a highly fragmented industry with no major players), but because ol' Billy Barr didn't like cannabis companies. This subjected those companies to months of intensive document production (hundreds of thousands or even millions of documents per company) and may have ended one merger due to the delay. Rank abuse of the enforcement process to harass an industry Barr didn't like, which consumed millions of dollars in time and resources from the private companies and gobs of tax payer resources (pulled from other active investigations). All to satisfy Barr's legal version of "get off my lawn"

-- Ginned up an investigation into dealings between California and carmakers willing to sign up to California's more stringent emissions policies. Quickly dismissed after costing private companies and taxpayers gobs of time and money.