School for Scoundrels(1960)

Hapless Henry Palfrey is patronised by his self-important chief clerk at work, ignored by restaurant waiters, conned by shady second-hand car salesmen, and, worst of all, endlessly wrong-footed by unspeakably rotten cad Raymond Delauney who has set his cap at April, new love of Palfrey's life. In desperation Henry enrolls at the College of Lifemanship to learn how to best such bounders and win the girl.