Except of course that they do:

"Texas freeze raises concerns about ‘ridiculous’ variable rate bills" (2021)

HOUSTON, Feb 23 (Reuters) - In Spring, Texas, about 20 miles (32 km) north of Houston, Akilah Scott-Amos is staring down a more than $11,000 electric bill for this month, a far cry from her $34 bill at this time last year.

"What am I going to do?" Scott-Amos, 43, said. She was among the millions of Texas residents who lost power during several days of bitter cold that caused the state's electrical grid, operated by the Electric Reliability Council of Texas, to break down. "I guess the option is, what, I'll pay it? I just don't feel like we should have to."

<https://www.reuters.com/business/energy/texas-freeze-raises-...>

This instance involves variable rate billing systems, where the cost per unit use can vary tremendously. There are also stories you'll find where equipment issues (broken water or gas mains, malfunctioning electrical equipment, failure to terminate per-minute-billed telephone calls, etc.). I can remember the latter featuring in some compendium of records (possibly Guiness) for a family who hadn't realised that they needed to hang up the phone between calls and got hit with a staggering (at least for the time) bill. More recently, data and roaming charges tend to be culprits:

<https://worthly.com/most-expensive/expensive-phone-bills-tim...>

In all of these cases, a significant problem is that usage is all but entirely divorced from metering, and people have no idea of what their actual usage patterns are until "invoice therapy" arrives.

(A term I'm borrowing from a friend, though I'll note that monthly feedback cycles on what are typically hourly/daily decisionmaking patterns proves a poor systems control theory match.)