A question about Lightroom - the crop tool

Every time I go to the crop tool I have to lock the aspect ratio. Every time.

Why? 

Is there a setting in Lightroom that I am missing? 

I rarely crop other than in the standard format with which I took the photo - why is setting so? It is illogical and irritating. 

And a waste of my time, every time I crop. 

Rick McEvoy Photography