I'm going to outline a couple must configurations I use in my ~/.ssh/config:

1. Automatically close connections on network failures:

   
   ServerAliveInterval 5
   ServerAliveCountMax 1
   

   This way SSH send an echo (a sort of ping) every 5 seconds, if didn't get a reply for "1" times it closes the connection.

   But if you're stuck in a session for some reason, you can always just press the following keys in order: <Enter>~..

2. Set up usernames so you don't have to type ssh username@company.com all the time, but just ssh company.com:

   
   Host company.com
       User antonio
   
   # works with wildcards too
   Host *.company.com
       User antonio
   

   just remember that rules are applied in order, so the first match wins. Run ssh -v company.com and you'll see something like debug1: /home/antonio/.ssh/config line 4: Applying options for company.com.