For me, it’s St Josemaria Escriva. I can never, ever forget his words: “Your ordinary contact with God takes place where your fellow men, your yearnings, your work, and your affections are.” (https://opusdei.org/en-ph/section/saint-josemaria/)
This means that however I treat these elements in my life also reflects the way I treat God. If I neglect my fellow men or my work, it also means I neglect God. This insight about sanctity in my daily life has turned ordinary routines into opportunity of growth for me. I know for sure that the results most often stay true to the effort I put in. But without me dedicating that piece of work to a higher purpose, I lose my will.
How about you?