Many people know that they are supposed to have a secure connection when logging into their bank's website or making an online purchase.  They are supposed to see a HTTPS on the address bar of their  browser but why not have it on Facebook too? Facebook has a lot of personal information and if you get targeted by a man in the middle attack, in simple words just hacked, you  are very exposed because there is no secure connection.  Below is how to enable by default, Facebook have a HTTPS connection.  

1) Log into Facebook

2)Account -> Accounts settings

3)Account Security -> change

4) Secure Browsing (HTTPS) ->  Check the box that says

"Browse Facebook on a secure connection (https) whenever possible"

5) Done!