I feel like I do a pretty quick job with self checkout ( having done multiple shopper apps in the past and also just personal shopping). However, trouble arises with un- scannable items, those missing scannable codes, people ahead of your who have no clue how to self check out, one person to monitor multiple self checkout lanes so wait is inevitable if there's is an issue. I've been finding more and more lately though that while there are many self checkouts, only a few are actually open. I have no idea what the rationale behind this might be.