May I stain my flooring?

Absolutely. You may choose any color in the rainbow, but some woods stain better than others. Red oak takes virtually any stain well (including a white stain); but maple, cherry and white pine can become blotchy if a sealer is not used first. However, in my book there are several down-sides to staining a floor. First, the darker the stain, the more it shows dirt. Second, if a stained floor is scratched into the underlying wood (not good, see below), it is more visible. And third, stain is merely thin paint. As such, it muddies the grain, locks the color in place for all time and prohibits the wood from aging gracefully. Other than that, ignore my advice and stain merrily away.