Not at all. Some of my favorite books are upwards of 900 to 1,000 pages or more. If i see an author I've enjoyed in the past has written a new, long book I tend more to get excited at the prospect.
Regardless of the length, I'm always a bit sad when a book that's giving me hours of enjoyment and escapism ends.
“Each book was a world unto itself, and in it I took refuge.”
― Alberto Manguel, A History of Reading