I have always been annoyed that dired mode opens a new buffer for each directory it visits. I typically only use each buffer once anyway, and they get in the way of the autocompletion when switching between buffers with C-x b.
Only recently did I learn that simply pressing a instead of enter or C-m makes it reuse the same buffer. Nice!
For some reason, the function is marked dangerous, but that's easily fixed:
(put 'dired-find-alternate-file 'disabled nil)