I have a few doors myself at home. Most of them are open all the time, but others are opened and closed on a regular basis (like the kitchen). Unsurprisingly, I don’t have the word PULL or PUSH plastered over the handle, I know which way they open. You might say that’s because I live there, well true, but then visitors to my house don’t have a problem either.

(img by rustman)
So why do large public buildings feel the need to label the action of a door? Most of the time this is because they have a push handle on a pull door or vice-versa. Wouldn’t it just be simpler to have a flat pushing panel on a push door and a stick-y out handle on a pull door?
The same applies to user interfaces. If there are devices that people recognise, then don’t be afraid to use them. Don’t try to be different just because you’re bored or want to appear original. I don’t care, I just want to get in or out of the fucking building!