One of my old colleagues asked me for a peculiar problem on CRM 2013 forms where the required field indicator was missing on the forms. Consider the example of out of box Opportunity Form here:

As you can notice, all the required field indicators are missing above. I just wanted to check upon the cause and found out that Microsoft has applied a setting which cause the indicators to move away. You just need to go to Options from Settings (top right corner of the CRM 2013 screen):

Then, disable high contrast on the screen:

Once you are done click OK and that will resolve the issue:

Hope it helps!