When I first started T.I. lessons I kept having a recurring dream about going to the pool and finding that they'd replaced the water with a thick clear goo, similar to hair setting gel. I'm sure my subconscious was trying to tell me something about my hand entry. :-)
The design of the pool walls may have an effect. I got talked into trying a masters meet last winter in a pool I've never swum in before. The pool deck was a good 18"/450cm above the gutter and I think they turned the circulation pumps off for the meet. I've never felt so fast in a 25m pool.