So, once upon a time, your door color meant something

[dixiegrrrrl]

3. In the South, blue front doors keeps the bad spirits from entering the house, they say.

One will often see blue doors and shutters.

I do know for a fact that that blue, even the palest tints of blue, keep winged insects away.
We have a large carport, it had a white ceiling, wasps and moths and other flying things would be buzzing around all the time, esp. flying towards the ceiling.
When we painted the house a calm grey, we painted the carport roof the palest of blue, it looks white to our eyes.
Not a flying insect in the carport since, except for mason bees, which are large bumble type, completely harmless.

As for door meanings, I found this, various web search sites:

In Scotland, homeowners would paint their front door red to signify that they had paid off their mortgage.

In Ireland, front doors are painted red to ward-off ghosts and evil spirits.

Many Anglican (Episcopal) churches boast red doors for theological reasons. This goes back to the Middle Ages, when the north, south and east doors were painted red, symbolizing the Blood of Christ, to indicate that churches were designated Sanctuary, where anyone was safe from danger. Some other mainline Protestant churches, such as Lutheran churches, have red doors as Wittenberg Cathedral, where Martin Luther nailed his 95 theses, had red doors, and by tradition, this marks such churches as Reformed churches