Yep - a lot of people assume, that because they're paying for it, it is a better way to go.
The price in the express lanes go up when local lane traffic gets heavier, so that people won’t clog up the express lanes. However, some people see that high price on a sign ahead of time and rightly guess that there is heavy traffic up ahead, so they dive into the express lanes. If enough of them do that, then those lanes also get clogged. It’s happened to the Miami-Dade I-95 express lanes in Florida.