People who realize they have bass problems usually will comment that it’s not the sound of the bass itself that is problematic, but sometimes you may hear them say that they are not getting the attack, texture and definition they would like.
As many have commented, these bass problems deal with how the speaker is interacting with the room. Most systems will have some bass reflections that cause both room mode issues (excessive gain in a small window of frequencies) and phasing issues (where the waveform conflicts with other waveforms at intersection points and manipulate or cancel them out). For example, an 80 Hz wave cycles four times and can intersect with a 20 Hz wave in a particular instance, which could amplify gain or nullify it based on its phase. In these cases, what is happening then is that the bass is “muddying up” the remainder of the frequency spectrum.
As hilde45 says, many are not aware they even have issues and are not aware of what they are missing. But when these issues are resolved, the tonal balance improves, and each frequency across the spectrum is better defined and perceived, helping the system itself to sound more immediate and resolving.