YOU SAID:
Let's not start this trip on such a downer.
INTO JAPANESE
そんなダウナーな気持ちでこの旅を始めるのはやめましょう。
BACK INTO ENGLISH
Don't start this trip with such a downer feeling.
INTO JAPANESE
そんなダウナーな気分でこの旅行を始めないでください。
BACK INTO ENGLISH
Don't start this trip with such a downer feeling.
That didn't even make that much sense in English.