It amaze me how although being at the SAME PLATEFORM i had come across so many different interface 

Take Reply and comment as example,

If you post something as question, reply will appear as comment, with the super small (and hard to click) comment button to open other's reply to your reply 

If you post something as Post, reply will appear as Reply (in text) 

We need a consistent UI. There is no point in having a different "Reply" and "Comment" 

"Humans do not always err. But they do when the things they use are badly conceived and designed."