Yeah, I qualified that statement because the research seems to be contentious

.
I specifically was thinking about ceiling vs floor reflections. Ceiling reflection everyone seems to agree can be bad. But Toole seems to believe the floor reflection isn't a huge contributor to our perception because we've adapted to it. Chapter 7.4.7 from the latest edition of his book:
"Very early in my explorations of loudspeaker/ room interactions I took note of the measurable effect of the floor reflection in steady-state room curves. It seemed like a problem that needed attention, so I devoted some time to modifying loudspeakers to minimize it, and followed through with subjective evaluations. I cannot claim to have been exhaustive, but I soon became frustrated when the curves looked better but the sound seemed not to have changed very much."
Furthermore:
"The Fraunhofer Institute in Germany constructed an elaborate listening room in which different room surfaces could be changed (Silzle et al., 2009). “Regarding the floor reflection, the audible influence by removing this with absorbers around the listener is negative— unnatural sounding. No normal room has an absorbent floor. The human brain seems to be used to this.”
He then goes on to surmise that we've adapted to floor reflections so it doesn't make sense to try to treat it. This doesn't
necessarily mean that we don't prefer good frequency response for the floor reflection, but it suggests we're less sensitive to it than others.
However,
other research has said that it's the worst of reflections though, so who knows =]