Anything under 30 and im probably out. Especially if there is any wind.
Clothing is the same kind of stuff I'd wear climbing or hiking. Inner layer is wicking fabric. Second layer is warmth. Shell layer is wind protection. Mittens are great and easy to pull on/off to make a shot. If its really cold I'll wear a balaclava under my hat.
Motivation is easy. I live in North Dakota. Play in the cold or say goodbye to 1/2 of your season.