Now when you walk around a room you do not hear all the sound come and go with your position in the room. This is because the pattern of boosts and cuts is different at every frequency, and that the spacing is dependent on frequency. At low frequencies there are large spaces between the peaks and dips in level, while at high frequencies they are very close together. Add in the fact that we have two ears separated by some distance, and that we naturally move around while listening, and we can understand why this standing wave issue is only of any concern at low frequencies. It explains why you may perceive large changes in bass from place to place in a room.
Some rooms have worse standing wave problems than others.
Many years ago Sepmeyer did a study of room dimension ratios. He showed that for rooms that had all their room dimensions related by low whole numbers, the standing waves at many frequencies tended to happen at the same points in the rooms. Rooms which had dimension ratios that were not simply mathematically related had their standing waves spread out much more evenly. Some years later another researcher showed how even for room with poor ratios, if none of the surfaces were parallel, the standing waves spread out more evenly in the room instead of bunching up. This is one of the reasons acoustical engineers often recommend non parallel surfaces in a room where sound is important.