For me, it was glove size and no padding. I have gone from wearing an x-small to a medium. I cannot tolerate any padding. In this search for the cause of my hand pain, I discovered that while I have small-ish hands (not tiny, though), I have very long fingers. No wonder my gloves were strangling me. I actually had an argument with the owner of one of the LBS's that sold the unpadded Botranger gloves I loved (which they stopped making). He told me that mediums would be huge on me, and that I would probably get them caught in the shifter. Then he saw me try them on, and he shut his mouth.
2015 Trek Silque SSL
Specialized Oura
2011 Guru Praemio
Specialized Oura
2017 Specialized Ariel Sport