Intelligent life in the Universe. Back in the late 1960s, early 1970s, I believed it could be quite common. Now I think it is very rare if it exists at all (except for us, of course). I am less sure about simpler forms of life, but lean toward thinking it is much rarer than many people think.
The Universe is an extremely big place! I can feel your skepticism though with regard to our own Galaxy. If there is intelligent life, it may well be hundreds or thousands of light years away. Which means it would be very difficult to have any meaningful dialogue with them.