This one at the safety induction tells you that time is important, but more important than time is safety:
There is no work so urgent or important that we can't take the time to do it safely.
I saw this one on a rig floor - encouraging you never to be shy when you have a question:
When in doubt - ASK. The only wrong question is the one you did not ask.
Of course some are great sources of entertainment - like this one which tells you to smoke only in designated areas.
Please do not smoke in here. Smoke is the waste left behind from your cigarette. You know what I leave behind after I drink water? How would you like it if I stood on top of you and pissed all over you? Respect my preference like I respect yours.
Of course no one really cares about swearing or cursing here. Why else would you see this in the main office?
How about a nice big cup of Shut the F*** Up? THINK before you say something stupid.
And then finally there is that sign which makes you think that inspite of all the safety they're promoting, there's always one sign too many. One that makes it seem like you're three years old and/or retarded. Like this one posted 35 feet above the ground on the rig floor:
Do not jump. Use stairs.