Yes, Virginia, you do have to obey ATC instructions
One of the repeated hot topics among pilots is whether a pilot who is not on an IFR flight plan must obey an ATC instruction in Class E airspace. On April 25, 2013, the FAA’s Office of the Chief Counsel answered with a resounding “yes.” In short, “Pilots flying in controlled airspace must comply with all ATC instructions, regardless of whether the pilot is flying VFR or IFR, in accordance with § 91.123(b).”
