Not all queues are created equal. Some have great theming. Some are deliciously air-conditioned. Some are not so fun.
For example (off the top of my head and at random) I enjoyed the queue at Tower of Terror in Disneyland Paris, but the one at Jurassic Park at Universal Hollywood is just a featureless cattle pen. (Or was when I was last there.)
Which queues have you enjoyed -- and which would you avoid?
And which do you miss out on a positive experience if you use Fast Pass or Single Rider?