Why 电灯泡/電燈泡?

[Peng]

I understand that the English idiom, "Third Wheel" refers to third person being with a couple and feeling left out. But I wonder why is 电灯泡/電燈泡 (light bulb) used to refer third person? How is it related to a light bulb?

[skylee]

Assuming that a couple or boyfriend+girlfriend like to go out on a date in a darker place (eg in a park at night, a cinema or a dimly lit restaurant), a light bulb is a third person who, like turning on the light, ruins the intimacy. Think boyfriend+girlfriend on a date with the gf's little brother ...

[roddy]

Skylee's explanation makes a lot more sense than the (British?) English equivalent of gooseberry . . .

[Snowy21]

Light bulb because like... a light bulb stands out... so... it's like... the third wheel getting in the way...

[Lu]

I got it explained to me as: the third person can only sit there with the other two and hold the light over them. Or something like that. Actually Skylee's explanation makes a lot more sense.

[HashiriKata]

A light bulb... can see everything! (And we don't want that, do we? )

[Alhazred]

"I got it explained to me as: the third person can only sit there with the other two and hold the light over them. Or something like that. Actually Skylee's explanation makes a lot more sense."

This would be close to the French equivalent "tenir la chandelle," though I reckon I had never thought of that before...

[magudo]

because "电灯泡" would "照亮"

and "照" also means "看管""监视""照看"

for example: 我出去一下，你帮我照看一下东西

[monto]

skylee

Assuming that a couple or boyfriend+girlfriend like to go out on a date in a darker place (eg in a park at night, a cinema or a dimly lit restaurant), a light bulb is a third person who, like turning on the light, ruins the intimacy.

Ya, Agree!

电灯泡 makes a play in dark under the light, the parties concerned may feel greatly embarrassed or uneasy.

[creamyhorror]

I view this as the couple sitting/kissing on a park bench with a lamppost next to them. The third person literally takes the role of the lamppost. Pretty close to Lu's explanation, actually.

[zozzen]

it seems to be a cantonese slang. Is it used in putonghua now?