For a specific example, "itadakimasu" (literally "I will take it.") spoken at the start of a meal is a complete bastard to translate to English. "Thank you for the food." would be a translation of the core spirit of the phrase, but it lacks the elegance and respect of the way it is conveyed in Japanese. "Amen" would be a western cultural/religious counterpart that most westerners could relate to, but this adds religious undertones that are not in the original Japanese.
Not to mention, "Thank you for the food." also overlaps with "gochisousama" (literally "Mr. Feast", "-sama" is an honorific) spoken at the end of a meal. Two very obviously distinct and different Japanese phrases, but the English translation ends up being more or less the same.
None of this is to say English isn't expressive, but Japanese takes the expression game to a whole new level; yojijukugo[1] are the epitome of this using just four words to construct and convey what would be entire sentences or even paragraphs in English.