Can a garage be too big?

No, if you have alot of tools and projects, but.........
Yes, if it is a 40x100 Quonsot and you are thinking about trying to heat it in the winter.
.......might as well be pi$$ing in the wind.......we (my buds and me) are thinking of building a shop within the shop just for the winter so it can be heated affordably.
we are renting it so spending alot on it is out of the question. thinking 2x4 framing and heavy plastic tarps