Each year in fall, the Bunkachō (文化庁, Agency of Cultural Affairs) publishes the results of its annual opinion poll on the linguistic state of the nation, officially called Kokugo ni Kansuru Yoron Chōsa (国語に関する世論調査, Survey of the National Language). This time, the survey asked about the acceptability of a couple of recently used polite expressions that are viewed with some suspicion.
The phrase that the largest number of respondents found problematic was "O-kyakusama, dōzo itadaite kudasai (お客様，どうぞいただいてください, Please eat/drink, dear customer)." Over 74 percent of the participants said they took issue with this expression. Since the verb itadaku is a humbling term to designate acts of receiving, including eating and drinking, it should be used only to refer to actions by the speaker, not when someone else receives something. What is needed here is a verb that elevates the other person, for example meshiagaru (召し上がる), with which the phrase in question would become dōzo meshiagatte kudasai (どうぞ召し上がってください).
The second most-disliked survey item basically suffers from the same defect. Seventy-two percent found fault with the expression "Sensei, kochira de o-machi shite kudasai (先生，こちらでお待ちしてください, Please wait here, teacher)." Again the problem is that the person who is supposed to be exalted ends up being addressed with a humbling form. However, this time it's not the verb itself that is inadequate, but the construction it comes with. O-machi suru is fine when you are waiting yourself, but when talking about someone else waiting, that person should be described as o-machi ni naru. Thus, the request should use "O-machi ni natte kudasai (お待ちになってください) or, more succinctly, "O-machi kudasai (お待ちください)."