My plumbing system, like others mentioned on this thread, has a cruel and twisted sense of humour. I have to turn the bath taps on and off half a dozen times before it'll stop vibrating and banging and reverberating through the whole house. When next door are using water, or the kitchen tap is on, the pressure drops precipitously, biding its time until I turn the bathroom sink taps up high. At this point it likes to go "HA! I HATE YOU" and return to full pressure, and of course the shitty sink can't possibly cope with that kind of onslaught.
The on-demand boiler delivers no hot water, until it does - a mere trickle, but hotter than the sun. It takes eight minutes to fill the bath deep enough to wash in. I've timed it. When the central heating is on it sneers at my attempts to use the hot water.
When the neighbour has a shower, it sometimes inexplicably causes the soil pipe to back up and flood the bathroom with blue, shitty water. The Victorians installed a very special type of sewer on the boundary between here and next door, a design that was discontinued after only a couple of years because it blocks at the first inkling of an actual poo, and which we've had to install a gate over, so it's actually accessible rather than being under a fence.
Sometimes the tap just won't run at all.
Once, I was running the kitchen sink and the tap blew off the top of the pipe. There was a geyser in my kitchen. I called for DP, who, after initially shouting, "Just turn it off", came in, realised what was happening, and reached past me, tutting, to use his manly strength on the stopcock. It eventually required several thwacks with a mini sledgehammer to shift.
And once, the washing machine exploded.