Something relatively simple, an electric steam iron, made vastly complicated by adding: pump; boiling unit; valves and safety valves, thermal cutout; a load of electronics; retracting lead unit; and an awful lot more plastic to contain it all. More to go wrong. And it has done so. Somewhere.

(Edit: I did eventually find the problem, a near shorted TRIAC that controlled the solenoid valve to let steam through to the iron. The valve was effectively open all the time, so steam would come through continuously. Replacement cost was circa £0.50... a bit less than circa £190 for a replacement of the same type of iron!)