The fact is, if you try to avoid holding up the line, many others before you have, and many others after you will hold up the line, likely for a much more worse reason. Yours is a legit reason for you to hold up the line and do so. It's the employee's and store's job to worry about long lines behind you, not you.
Enjoy any good things, even the little and menial ones, as you will never know what impending distresses could descend upon you in a moment.
If I fail to adapt to the fault of others, it is my fault.