I have to respectfully disagree. To make such a statement is a generalization. Saying someone else will be comfortable with a particular size phone or that eventually it will "feel normal" is to make an assumption that even if their hands are larger or smaller it won't matter to them. There is no such thing as "one size fits all". The phone can't shrink, and your hands can't grow so it becomes a physical impossibility to use without two hands.
I tried to use the Nexus 6, a very thin bezel phone with a 6" screen, and found myself struggling to touch areas of the screen and operate it without using two hands. It's just not possible without risking dropping the damn thing. My fingers just aren't that long, my palm isn't wide enough to hold the phone and stretch to reach anywhere beyond about 4/5 of the width, and about 5/6 of the length of the phone.
I see plenty of people in the same physical size range as myself (5'6"), who have 5.5" to 6" phones but they are obviously struggling with their Phablets. The Samsung Galaxy Note 4 seems to be the one I see most often. They look so uncomfortable using it, and when there's an Otterbox on them, then they REALLY look humongous. However it seems to be some kind of status symbol perhaps, as well as perhaps presbyopia setting in that seem to be the big motivating factors for such a large phone. Also, obviously web pages and other things viewed are much closer to natural in size with such a large screen, but the physical size of the phone is not ergonomic, IMHO.
I also say that such a large phone looks really very odd when held to the face to make a call.
