I hate this saying more than any right now. I understand it and I know that we should all be thankful for the job we have. In that being Thankful, it is implied, by the one who is saying this, that there should be no complaints about things we need to do that may or may not be our job or the lack of responsibility on the part of others.
That is a load of crap!
Trying to move up or get more is frowned upon to the point where someone will say this saying to you. At least in this place.
Thankful to them also means to “just take it” when you are doing your best and yet raises have been frozen or the match on your 401k is eliminated, but we are supposed to just be thankful we have a job and be happy about it? What happened to making your employees happy so they are happy in their position and want to work hard and have good morale? These things alone create job satisfaction which create better responsibility and better health.