He tries to curry favor with the boss by always agreeing.
curry favor
idiomTo seek to gain favor by flattery or attention.
Origin
folk etymologyOriginally from a French poem Roman de Fauvel, written in the early 1300s; Fauvel was a conniving stallion, and the play was a satire on the corruption of social life. The name Fauvel points to the French fauve (“chestnut, reddish-yellow, or fawn”), another sense of fauve meaning the class of wild animals whose coats are at least partly brown, and the medieval belief that a fallow horse was a symbol of deceit and dishonesty. The phrase curry Fauvel, then, referred to currying (“combing”) the horse, and was altered (as folk etymology) by later speakers to curry favor.
The new employee constantly brings coffee to the manager to curry favor before the performance review.
By offering excessive praise to the committee members, the politician hoped to curry favor and secure their support for his controversial new proposal.