It's amazing what the human brain can infer from just a few simple cues. It can think that an inanimate object looks like it has a face, and make ridiculous comparisons between entirely unrelated concepts that somehow make perfect sense. Perhaps the funniest way in which our minds work (if we're corrupted enough) is where we find innuendo and rude things.
Whether you have a dirty mind or you simply know too much, double entendres are in more places than you might think. We have to be thankful for that, because some of them really are amusing. While the prudes might tut and frown at such occurrences, it feels nicer to just think of them as one of the many little benefits in life. Double meanings aren't always funny, but hopefully most of the examples below are. So long as nobody starts getting too obvious, we can let these things pass.