Leather Cuirass Lorica Musculata, I used to think no way but

[Tarbicus]

(soldiers like to stay comfortable, and that I bet has never changed)

I'd bet otherwise. How would you feel wearing these?:
http://www.scottishweb.net/family_tree/ ... ldierW.jpg
http://www.vikingsword.com/laking/lak031a.jpg

You should define what a Roman would think of as comfortable.

As for the purpose of armour being to make a man feel protected even when not, surely the start of the first fight would see that confidence evaporate in an instant.