There is no fucking way that anyone can sum this shit all up in a simple sentence like that, which would apply to every situation.

Different headphones and speakers have different frequency response. If you're using speakers, the acoustics of the room can have a large effect as well. Are we supposed to go out and buy the same equipment the person mastering used? Build a specific room layout for the specific acoustics intended per track? What if the person mastering already took responses of different equipment and rooms into account? It's not like you get "intended listening guidance" notes with most music.

Personally, if I can tune the EQ towards a flat response graph for my particular headphones I will (Poweramp for Android has these presets built in for a ton of headphones, but you have to apply them yourself), otherwise I don't fuck with it unless some section sounds particularly blown out. My car overenphasizes bass, which is fun most of the time, but I turn it down for some tracks where it drowns out finer details.

Ultimately there's a shit ton that is up to taste.

Unless the frequency response of one's hardware is perfect, it's advised to do the exact opposite and apply the eq bringing it closer to the ideal, e.g. with the AutoEq measurements for headphones.