Lights flickering in the house
Flickering lights in a house come down to a loose bulb, a mismatched dimmer or a heavy appliance starting up, and the best clue is when they flicker. The on-and-off troubles of an ordinary week can be traced the same way.
What it may mean
A flicker is the most annoying kind of problem: it comes and goes, and it often stops the moment you stand under the light to look. Electricians track it down by watching for a pattern. Does it happen when the dryer starts, when the wind blows, only on one circuit? The timing gives the cause away. The same patience works on the stubborn, on-and-off troubles of an ordinary week: the mood that dips on Sunday nights, the argument that flares only when someone is tired, the energy that drains after a certain kind of meeting. Rather than worrying at each flicker, you could note when it happens and look for what it is tied to. Old English belief saw a spirit in a candle burning blue, and Belgians saw trouble in a flickering altar light; for your lamps, a notebook helps more than a guess.
Depending on how you saw it
Flickering when an appliance starts
Lights that dip when the washer, the dryer or the air conditioner kicks on are reacting to a big motor pulling extra current for a moment. Every circuit is drawing on the same supply. Which demanding task in your day dims everything else around it as soon as it starts?
One bulb stuttering in a fixture
A single bulb that flickers while the others hold steady is often loose in its socket or near the end of its life. The problem is small and local. What worry have you treated as a whole-house problem when it is really one loose bulb?
LED bulbs flickering on a dimmer
Many LED bulbs flicker on dimmer switches designed for old incandescent bulbs, because the two do not work the same way. Neither part is broken; they are mismatched. Which two parts of your life work fine on their own but clash when they meet?
Every light in the house flickering
When lights flicker all over the house, or a switch buzzes or feels warm, the cause may be in the wiring, and it is worth calling an electrician. Some flickers are safe to live with and some are not. Which recurring problem around you has gone past a quick fix and needs someone who knows the system?
Why it happens in nature
Most flickering comes from a bulb loose in its socket, an LED bulb on a dimmer it was not made for, or a large appliance briefly drawing extra current as its motor starts. Flickering throughout the house, buzzing switches or warm outlets can point to loose wiring or a problem with the electrical service, which an electrician should check.
What folk beliefs say
England
Melton's Astrologaster, an early English book quoted by Brand, lists the belief that a candle burning blue is a sign that a spirit is in the house or not far from it.
Source: John Brand; Henry Ellis (ed.), Observations on the Popular Antiquities of Great Britain, vol. 3 (1849), vol. 3, p. 181. View the page
England
Sir Thomas Browne, quoted by Brand, allowed that candles might really burn blue and dim when "spirits" appeared, if the air was full of sulfurous fumes, as often happens in mines.
Source: John Brand; Henry Ellis (ed.), Observations on the Popular Antiquities of Great Britain, vol. 3 (1849), vol. 3, p. 181. View the page
Belgium
In Belgium, if the "eternal light" kept burning at a church altar was seen flickering, people took it as a sign that something was wrong in the parish.
Source: Cora Linn Daniels; C. M. Stevans (eds.), Encyclopaedia of Superstitions, Folklore, and the Occult Sciences of the World, vol. 2 (1903), vol. 2, p. 1177. View the page
To reflect on
Which on-and-off trouble in your week would make more sense if you noted when it happens?