Late night big top headliner is the main bottleneck innit, quite often gets to the one in/one out stage. Used to be bad queues for the late night tipi/secret sets too but last year seemed easier or maybe I just got lucky.
The Boat you need to get there early for a good view if there's something you really fancy.
Oh and closing the folly between acts always causes a big queue too I guess.
Rarely felt the garden too packed to enjoy, can be a pain leaving if you're trying to rush to another stage as a popular set ends I guess, tis what it is.
None of the above ever really bothers me tbh so I guess it's acceptance, there's always something else to see.. queues for food are more annoying for .e and again, last year was fine for that.