Ok, so if you're in college but don't eat in the student cafeterias all the time and/or don't just order takeout, or if you're an adult I think you'll get what I'm getting at.  Otherwise, maybe not.

Self checkout. 

Now people presumably smarter than me will say here that people who use self checkout are deluding themselves and the grocery store cashiers are ALWAYS quicker than doing it yourself.  Now, in all fairness, they're probably correct.  I've never heard the argument (the people smarter than myself rarely would actually make an argument for their hypotheses), but if I were to venture a guess they would say that cashiers are paid to do their job and therefore have more practice, and are better than the average consumer at a grocery store.  Yet for a lot of things (lunches in particular) I always use self checkout.  I pretty much get the same thing every day for lunch from the local harris teeter (sub, bag of chips, drink) and once I get started at the kiosk, I can usually check out in a minute or so, which when there's not a line or when there are just likeminded lunch-buyers at the self service area, is pretty good.  Plus usually the housewives making large mid-day grocery trips usually use the regular checkout, so that's implicitly a longer wait. 
However, sometimes a serious coupon-hunter, or someone paying with a non-standard method decide they want to use the self-checkout lanes too.  And inevitably they get stuck.  Today was a perfect storm of this.  One of the four self checkout lanes was broken.  This is rarely a problem as there are 3 others.  However when I pulled up in line (2 people in front of me) there were 3 people in line, 2 of which were of the 'coupon hunter'/'housewife' variety.  The third was with someone paying with some sort of alternate method (not sure if food stamp or gift card, but she wasn't pressing the credit/debit button on the screen).  So here's what happened:
the housewife lady had a large order,  not too bad because she seemed efficient at scanning her goods so I gave her a pass.  The coupon lady was buying alot of produce, which means using the touchscreen to key in PLU's which ALWAYS does make using the self-checkout slower because people aren't very touch screen friendly by default.  The alternate payment lady was buying what looked like lunch.  But it was taking forever.  So after standing in line for like 2 minutes, the people in front of me go to a full service aisle.  After another couple minutes the housewife finished.  My turn.  I watched the alternate payment lady for a minute of those last 2 minutes trying to pay - over and over again.  When I stepped up, she was visibly and audibly getting frustrated.  Meanwhile the one dude assigned to fix problems at the self checkout kiosk had the manager come over to look at the broken kiosk.
Here is where what transpired to make me write about it happened:
First, the alternate payment lady's phone rang.  SHE ANSWERED IT.  I mean, not like you're having trouble and need to focus and there isn't a line or anything.  On top of that, she answered it just to say "I'll call you back" and the person on the other line hassled her.  I know that sounds like I'm just needling, and in a way, I am.  But what frustrates me about all of this is the general lack of self-awareness here.  So after a minute, I'm beginning the pay process.  At this point alternate payment lady is finally off the phone and asking for help from the self service dude- which he pretty dutifully goes over to help (remember he's been working on the broken kiosk until this point).  It's at this EXACT point coupon lady's coupons wont.... something....  I say this because she had trouble communicating clearly.  It sounded like her coupons wouldn't scan, but i couldn't tell.  And here's what frustrated me:  She was not aware of the fact that the kiosk dude was actually helping (and talking) to the alternate payment lady.  She just started talking at him, repeating herself, and making no energies to seem like she was willing to wait her turn, be patient, or recognize that the kiosk dude was actually busy at the moment. 

After another 30 seconds I had my goods in my grocery bag and gave a knowing smile to the people behind me in line (also lunch purchasers like myself) and made my way out of the store.  Of the 5-6 minutes I spent in line, those two people checked in probably 3 items each.  In the final 2 minutes I did 3 items and paid and walked out of the store.  Ironically when I was driving away, I saw the alternate payment lady walking out of the store looking flustered with no groceries in hand.  Not sure if she didn't have the money or what...

Anyways- my point to all this is I agree in principle with the anti-self checkout argument.  It is slower.  But, so long as people who have a desire to check their own goods out and to understand  how to work a particular self-checkout machine, there's reason to use self-checkout.  Of course, a lot of people use self checkout when they shouldn't (buying produce, large shopping order, paying in a non-standard way) and that certainly makes the experience worse.

Ehh- or I'm an asshole and shouldn't complain so much.  In other news on my way out of the parking lot I saw a blue mitsubishi eclipse driving in.  De-badged.  Rebadged with a ferrari badge.  Now that's something really bad.