If you cannot explain the purpose of every set and rep, much-less every exercise, then you are going to remain frustrated with your lack of progress.
While trying to target multiple things at once (fat loss, muscle growth, strength improvements, etc.) seems really appealing, the truth is you are not going to get very far pursuing them at the same time.
This is the very thing that ends up prolonging workouts with things that are not necessary and may even be detrimental to progress in any area.
Figure out your highest priority goal first and then focus all of your efforts into it. You will be amazed at how your body begins to change.
And you will be in and out of the gym faster than ever.