Seriously, this has to be the most annoying thing when I'm at a coffee house.
I'm on a Chromebook and never plug into an outlet. I get about 5 hours out of the battery.
It's very liberating to be able to sit where I please and work.
Also worth considering, offering numerous outlets invites people to spend hours in a coffeehouse, nursing a $1.50 iced tea while working/playing on their laptops. They take up valuable real estate, a problem for small joints with few tables. Worse, they often refuse to buy anything, simply taking a table and plugging in. I've watched many potential customers walk in, look around, and walk right back out when they realize there are no available seats.
This is a big problem for joints near colleges.
As for the most annoying thing I've experienced at a coffeehouse, it's not the lack of outlets. It's the loud, caterwauling women who travel in packs and shriek like hyenas when they hear something they consider funny. Worse, many of them bring their offspring, which would be fine if they had the class and awareness to prevent them from bothering other customers.*
Unfortunately, women seem to think everyone loves their brood as much as they do. They also tend to be oblivious and narcissistic, neither of which helps the situation.
Back to outlets... at the moment, I'm sitting at Panera Bread. Got 15 tabs open, streaming Liquid Tension Experiment, and working in Google Drive. My battery says 3 hours, 14 minutes left (I've been here awhile and didn't arrive with a full charge).
No outlet.
But no tears. Life is good.
* I can tell you stories.