You could have a completely even histogram, apparently no blown highlights, no lost blacks... yet your subject could be too bright or too dark.
In the case of my work, the background is often irrelevant to me. I don't care that much if it's lost to blacks or blown out in whites. What I do care is that the skin tones are well exposed.
So when I zoom out and get lots of background, the histogram can look pretty jacked... most of the time to the skewed heavily to the left because I light so selectively.
But the histogram is only part of the story. If I relied on it solely to expose the subject, then based upon the situation above (where most of the data is in the darks on the left), I'd have to increase the exposure to even out the histogram... yet in doing so, I'd overexpose the skin tones.
Just remember, not everything is what it seems. Use your eye to figure out what looks good.