We've all known or heard of people who in their early 40s suddenly leave their marriage, change jobs, get a tattoo or sell everything and move to Bora Bora. When it happens you know that the Uranus Opposition has hit them hard. Uranus in our chart shows us where we are unique and different from others. Got Uranus in the first house (like me)? You will dress and look different with your own unique style. In the fourth house - your home and family will be quite different. Got it in the the 10th house - you will have a unique and strange career path to others.
When we hit the Uranus opposition, he comes calling to ask us if we've been living up to the unique path he has set for us. How have we used that gift? Have we embraced it? Or have we tried to deny and squash it in an effort to conform to others' expectations. If we have not owned our quirks and accepted ourselves, he will hit us hard. This is when some people wake up and realize that they have not been living there's souls calling. That they have caged their wildness, put a beige suit on it and expected it to perform for others. Many see this as their last chance to get on with the business of following the path of their soul.
A funny thing happens in your early 40s - you stop giving a damn so much about what others think. Instead of conforming to the expectations of others, you are more likely to say "screw it" and do what you want. This is Uranus coming to call at the half wayish point of your life. You are not a kid anymore, but you are not old either. What are you going to do with the next half or so of your life (personally I expect to live to 100, so its not quite halfway for me I hope)? Depending on how true you have been to yourself you may have to make minor adjustments or major ones to course correct. If you have to make major ones, be prepared for the shock you may give others. Then again you can just ignore it, and many people do, and guarantee that your next 40 - 50 years (or whatever you have) will be miserable.
Personally I have not found this point too difficult. I'm in a great relationship and feel no urge to run away and join the circus. I did also have an eclipse on my natal sun recently (another subject for anther day) which combined did give me a bit of a slap in the face from the Universe. It said - "get on with creating things, because if you don't I will give you an breakdown. And don't worry what others think, like what you like, say what you need to say, and be who you are." So not too terrible, so far. Then again I never had much trouble with being different.