DSP/EQ crash course for Dummies.
EQ is for adjusting the room impact in the bass and correct the speakers near field response over aprox. 500 Hz. It sounds most natural, if the sound from the speakers has approximately the same timbre as live musicians would get when performing in the same room. It is also important that the dispersion pattern from the loudspeakers is fairly constant with frequency, so that reflected sound and reverberation do not have a completely different timbre to the direct sound. A good target curve falls by about 1 dB/octave, but is room, speaker and listening distance dependant. This tilt is the normal frequency response in a normal listening room, of a loudspeaker with a flat on-axis frequency response, when measured in an anechoic chamber and with a fairly normal dispersion characteristic. If you eq it to a flat response in the listening room, it is the same as a speaker with a rising frequency response on the axis in an anechoic room - i.e. thin and shrill sound, and then definitely a speaker that "measures poorly". Again, this is very well known, and no one who has played with eq and understands a bit of what they are doing, would set up a system like this.
So what EQ can do for your frequency response, is to even out the room impact and the often relatively nonlinear near field response from the speaker. If we translate it to the more traditional part of hifi where you share listening impressions, we can perhaps compare it to a sound were "nothing sticks out". When people write this about a sound experience, it is usually a positive characteristic.
But then again, in this idiosyncratic hobby, for many it is precisely a point, that the system should produce a sound, in addition to the original signal, aka all these buzzwords as "warmth", "soul", "human connection", "musicality" that should be added to all parts of the playback.
The rest of us who just wants to listen to the music and not the system, we want to have it reproduced as it was intended/recorded.