The biggest anti-pattern is the stateful VCR-like digit displays with a couple buttons. They're somewhat going out of style because more stuff has touch screen

The biggest anti-pattern is the stateful VCR-like digit displays with a couple buttons. They're somewhat going out of style because more stuff has touch screens or can be controlled by a smartphone. But lots of audio equipment still uses this "pattern". And thermostats have it. I'm a programmer and I still have problems figuring out that their state machine is without the manual. I just bought a $20 clock with the same issue. It doesn't help when one of the actions is "hold a button" either. There's no feedback as to what action you performed -- did I hold it for long enough?