Whenever I open a folder on a remote network share that hasn't been opened since I last booted, Finder displays this animated spinner in the bottom-right (see picture below) for about 30 seconds and won't display any of the folder's contents until it's done doing whatever it's doing.

This makes browsing the share painfully slow for seemingly no reason. Why's it doing this? I should note that I've disabled .DS_Store files littering network shares using defaults write com.apple.desktopservices DSDontWriteNetworkStores true, so maybe that's why. I'm kind of hoping it's something else, though.