I usually go topless (as in hoodless ) in summer too, but not on the longer/deeper dives..
As far as drysuit/wetsuit, I tend to get cold easily and I don't like the 'constriction' of a wetsuit, so that's why I go dry 365 days a year
Exactly. Plus, there's the matter of thermoclines, where it can be 72 F. on the surface, but 60 F. at 100 ft.
The other variable is liners, of course. You can adjust the thickness of the liner that you wear, to adapt to various conditions.
"Blessed are they who learn from their mistakes. For they shall make, if not necessarily fewer of them, different and more interesting ones."