When putting cards in envelopes, which way are they supposed to face?

[Spoooon]

It seems to make sense to have the front of the card face the back of the envelope, that way when you open it, you get to see the front of the card.

But if the envelope is white, you would then see all the crap on the back of the card through the front of the envelope.

Is there some guideline that we're supposed to follow?

 

[Banana]

When I open envelopes, the back of the envelope is facing me.

Card should face the back

 

[Spoooon]

Sounds good to me.