We recently spent over €4,000 on a new heating system for our house. It's a very clever system that adjusts itself in line with the temperature outside and can be set to heat just your water or just your radiators and no water, whichever you prefer. However, it turns out that you can't just turn it ON when it's cold out. You have to fiddle with the settings to reprogramme its start and stop times. There's no "boost" setting that turns the heat on for an hour and then turns it off again.
There is NO BLOODY ON button that just turns the effing heat ON.
So stupid. See, that's what happens when you don't ask anyone for feedback before you start production on something.