When there's 0 likes the data is missing from the JSON but when there's 0 comments it actually displays "0 comments" in the data.
 
Example Graph API JSON response

{
   id:"513086950_10150999823946951",
   from:{
      name:"Joe Jiko",
      id:"513086950"
   },
   message:"Speaking of the graph api, when there's 0 likes the data is missing from the JSON data but when there's 0 comments it actually displays \"0 comments\" in the data.",
   actions:[
      {
         name:"Comment",
         link:"https://www.facebook.com/513086950/posts/10150999823946951"
      },
      {
         name:"Like",
         link:"https://www.facebook.com/513086950/posts/10150999823946951"
      }
   ],
   privacy:{
      description:"Public",
      value:"EVERYONE"
   },
   type:"status",
   application:{
      name:"JoeJiko.com",
      namespace:"joejikocom",
      id:"160372647359458"
   },
   created_time:"2012-08-18T04:05:46+0000",
   updated_time:"2012-08-18T04:05:46+0000",
   comments:{
      count:0
   }
}

Why would they do this?
I'm now forced in my application to check if likes are undefined whereas it's unnecessary to do so for comments.