When UPS  drops off a load of boxes, they are not cartons of shirts. They are boxes of money.
There is a financial risk you are taking for every job in your system. For each shirt that is unaccounted for, missing, or the wrong style or color, that could end up costing you money. Receiving’s number one job is to prevent financial disaster. 

But, there is a problem. The clock is ticking.
The clock being that Production needs to start on that job soon. This is why the mandatory expectation for Receiving is that any shirts coming in today, must be counted today.
 No exceptions.

 There is a proper way to do this too.
First, the packing slip that is attached to the box is used and the contents of the box are checked against it. What you are doing is verifying what is in the carton. Does it match? The slip is initialed and dated by the person counting so that everyone knows who verified the contents. Then, the packing list is checked against the system to ascertain if it matches to the order.