 The band were not usually present for the stereo mixing sessions.While Martin recalled it as having been "a very joyful time", Smith said the sessions revealed the first signs of artistic conflict between Lennon and McCartney, and friction within the band as more effort was spent on perfecting each song.This also manifested in a struggle over which song should be the A-side of their next single, with Lennon insisting on "Day Tripper" (of which he was the primary writer) and publicly contradicting EMI's announcement about the upcoming release.