1970's
That if you dared to swallow chewing gum it wrapped around your heart and caused it to stop.
That my relatives lived over the hill yonder. Well they turned out to be a seven hour car journey so a bit further than the hill.
That it's so dirty in the north everything has to be boil washed to get the dirt out. 
Also had to wait an hour after eating to go in the water. I remember eating a sandwich on the beach as a child and being too scared to paddle to my ankles afterwards.
My dad told me I'd been born in a bucket. Said with such a straight face and backed up by my mum that I was almost eight before i realised it couldn't be true. I felt very rejected for a long time thinking they had left me in a bucket. It must have been so absurd to them it was funny and I was a sensitive, easily to wind up child
Always hang a horseshoe with the ends pointing up so the luck couldn't fall out. Also if you carry (a very heavy) horseshoe it must also be carried in the same fashion so the luck couldn't fall out.
Never open an umbrella indoors. Never bring an open umbrella indoors.
Don't pass on the stairs, very difficult in department stores.
Throw spilled salt over your left shoulder to blind the devil.
Count your magpies
Always buy white heather from a peddler.
Never go under a ladder even if you have to move into oncoming traffic to avoid this.
If you swallow an apple core you'll get a tree growing in your stomach.
If you went outside with damp hair you'd catch a cold.
Money spiders in your hair bring you money.
If you didn't tuck your vest into your knickers you'd catch a cold. Not very cool to be told this as a teenager begging to have a crop top.
That wearing red nail varnish indicated you were a loose woman.
That wearing an ankle bracelet was a way to indicate you were a prostitute.
When Channel 4 was launched apparently it was to risqué for under 18's to watch, and ITV was low quality production. BBC only for us 
That radio 1 was also too risqué and not to be listened to. God forbid I might want to watch Top of the Pops.
No drink until after your meal as it would spoil your appetite.
Sip orange juice, it's not a drink it's a treat.
More than 6 inches of water in a bath is excessive.
Tin foil is incredibly expensive and must be washed an reused. I discovered once I left home that it wasn't at all expensive.
Shampoo was too expensive for children, we used washing up liquid and had very knotty hair.
Bread and butter must be eaten with fish and chips.
Rum in a baby's bottle helps it sleep.
Tea in a baby's bottle helps it wake.
So many... some of which I can't get past today.