Which speakers did you find bright, fatiguing or just disappointing in some way?

This is a generalized question. It depends greatly on your ears, your room. It depends greatly on what you are feeding into those bright harsh sounding speakers. If you are using aluminum or titanium drivers, horn compression drivers they can seem harsh or bright on the wrong electronics. I found using a tube amplifier smooths out the harshness and instead of being harsh and bright it is detailed and smooth and can listen for hours with no fatigue.. Certain solid state amplifiers will make bright speakers sound harsh it is all how you set your system up.

Disappointing speakers for me:

Wilson Sophia (original version)
Aerial Acoustics 7B
Roman Audio Centurion
Meadowlark Shearwater HR
Usher X929
Von Schweikert VR2

Paradigm persona series, that beryllium Tweeter and mid-range are so hard bright and cold it's not even funny.

JBL and B&W.

Fatiguing speakers seem to be best suited for home theater.  That’s where I put my Def Techs.