Switches. Over the last couple of years I've had to discard a hob, an oven and a kettle which were working absolutely fine, and were 98% sound, because flimsy switches had broken and could not be replaced. I've managed to bodge a repair on our Electrolux cooker hood - a thousand pound piece of kit, relying entirely on a switch so badly designed that
every switch is connected only by a tiny tab of perishable plastic at the top. Not only that, some genius at Electrolux has designed it so that the actual switch is not located centrally, but off in one corner, setting up a leverage point that positively invites a slightly over-enthusiastic prod to twist and snap.
FWIW, the hob and the oven were also Electrolux. Not that I'm pissed off or anything, but certainly I for one will never buy anything Electrolux ever again.