During the early stages of Japanese study, the language is often divided into words and phrases that are extremely concrete — lessons themed on topics such as 家族 (kazoku, family) or 動物 (dōbutsu, animal) to learn sets of vocabulary — and those that are more vague.
The vague category includes set phrases like お邪魔します (o-jama shimasu, literally “I will be a nuisance,” which you use when entering someone’s home) and よろしくお願いします (yoroshiku onegaishimau, literally “please treat me well,” used in a variety of situations such as when making a request).
The concrete words associate easily with information we already know and are relatively easy to store in mental memory banks. The vague phrases, which are often culturally specific, require repetitions and context to gain familiarity.