What went wrong with this shot D5100 with f/1.8 lens

Umm..No.  Seems you mis-interpreted the entire post.

I knew from the start that the problem was my use of the camera, not the camera itself.

Boggles the mind that you would just jump to conclusions rather than perhaps inquiring and clarifying what I was trying to convey.

In typed words it is not always so easy to understand the intent - best to ask polite questions rather than jump to offensive remarks.

My 2 cents