There’s a song whose lyrics include Must I always be waiting on you and I can’t always be waiting on you. It’s a love song, of course. (What song isn’t a love song?)
The song seems to be about a man who’s had just about enough of sitting around and waiting for a woman to come to her senses. (Doesn’t that sort of thing usually happen the other way around? Aren’t women always honest about their feelings?) Well, good for him; who wants to sit around and wait forever on the chance that someone else will straighten up and fly right? Right?
But back to my grammar point: When I hear must I always be waiting on you, I can’t help picturing him wearing a bowtie and holding a tray of canapés and caviar. Waiting on should be reserved for what a server does for people in a bar, dining establishment, or cocktail party; he or she waits on them.
If you’re sitting around and doing nothing until some man finally tells you that he’s always been in love with you, however, then you’re waiting FOR him—and you should have better things to do, as well as more self-respect than that.
Don’t use wait on (serving someone) for wait for (putting your life on hold until someone else decides what you should be doing). We wait for colleagues to show up at the morning meeting, we wait for news about the latest political scandal——-and we wait for the people we love to come to their senses.