I seldom go into JoAnn's without a long line to wait in.
i think they simply don't want to pay for more employees to work. I was completely shocked when I stopped on Sat as I only wanted some glue. The first employee actually took me over to get it. An then, no one was in line. She did tell me that they had been very busy all day which means lots of lines.
I seldom go when there are sales. When I need something, I use a 40% off coupon.