YES. Especially between services. I once read an Army Commendation Medal citation for a soldier who "bravely" put out a small engine fire (in garrison - not combat...). The bar is much, much higher for USMC (i.e. a company commander's end of tour award if he knocked it out of the park). But inter-unit variability is also high. Not that there is something wrong with doing it one way or the other, but it should a) be consistent, so you have some idea what it meant, and b) actually mean something. Like many above, I've gotten awards I didn't think I deserved and then didn't get awarded for things I actually did.
If I could get on my soapbox - while, for officers, awards matter little other than pride - an appropriately awarded NAM, or even a meritorious mast or certificate of commendation (official pats on the back) really can mean a lot to a young enlisted guy. Used effectively, it can be a great motivational leadership tool. In the end, that's why we're in the service, so please take the time to do it right and recognize your young men/women who do a good job!