Asubornating conjunction is used to

The subordinate conjunction has two jobs. First, it provides a necessary transition between the two ideas in the sentence. This transition will indicate a time, place, or cause and effect relationship. Here are some examples:

   Louisa will wash the sink full of her dirty dishes once her roommate Shane cleans his stubble and globs of shaving cream from the bathroom sink.

   We looked on top of the refrigerator, where Jenny will often hide a bag of chocolate chip cookies.

   Because her teeth were chattering in fear, Lynda clenched her jaw muscle while waiting for her turn to audition.

Explanation:

People worry about it mostly because when people plagiarize, they are copying someone else's written work and are not giving credit to that person or quoting them. I think of it as literary theft. 
Hope I helped. :)