BismilLaahir Rahmaanir Raheem
One of the companions of the Prophet, Usamah bin Zaid (May Allah be pleased with them) reported: The Messenger of ALLAH (PBUH) said, "He who is favoured by another and says to his benefactor: `Jazak-Allah khairan (may ALLAH reward you well)' indeed praised (the benefactor) satisfactorily.'' [narrated by Imam At-Tirmidhi].
Meaning If one is unable to return someone's kindness with kindness, he should say, "Jazak-Allahu khairan (may ALLAH reward you well).'' This means: "I am unable to reciprocate your kindness. May Allah grant you the best reward for it.'' Obviously there is no match for the reward that one gets from ALLAH. For this reason the Prophet (PBUH) said that it was the best of the praise for a benefactor. From this teachings it's important we apply our Islamic identity for rewards instead of emulating the kuffar.
Islam is a way of life not just any other religion as such all we do must be within the teachings of the religion so instead of saying "Thank you" to your Muslim colleague, do them more favour with prayers by saying "JazakAllahu Khairan" so I say Jazakumullahu khairan for reading my reminders
May ALLAH keep guiding us and aid us to apply whatever we learn from the Prophet of mankind and jinn kind sallallahu alaihi wasallam AMIN