As a windows convert I had one major problem that took me probably about six months to overcome during my “switch” process. Opening files with the return key was a crucial part of my daily routine. It took me a long time to realize that there were alternative key combinations to get the same results on my sexy new mac. If you want to open a file with the keyboard navigate to it with your keys and hit the command key(⌘) and the down arrow at the same time. Alternatively, you can also hit the command key and the letter “o” key at the same time.
⌘ + down arrow
⌘ + O (oh, not zero)