Whenever you read about random knife attacks in public places, does it make you more attentive to what people around you are doing when you are walking along the street, waiting on train platforms or shopping?

Some. But I've always had a decent base level of situational awareness. Turned up a bit in crowded spaces and busy train platforms.

The chance of being caught up in such a situation are incredibly tiny but they are not zero, and you can say the same thing about being struck by lightning or falling through a sinkhole.

While you can take certain precautions, you can't live your life being ruled by fear. Sometimes bad stuff is just going to happen.

My situational awareness changes depending on the setting, time of day, and who I'm with. These reports of course raise the hairs on the back of your neck for some time, and that's good because it reminds you to stay sharp. @Hawk sums it up nicely:

While you can take certain precautions, you can't live your life being ruled by fear. Sometimes bad stuff is just going to happen.

My advice for this is to stay vigilant, but not paranoid. And always wear something you can move quickly and freely in.

No, most of the "random" attacks in Japan are not random. They are not looking for a specific person but most seem to be a target weaker than the attacker.

No. I’m usually aware of my surroundings and the people who act a bit odd. So much so that my wife complains I’m too aware.

Not one bit, I also do not believe it is totally random. There are others around. However, I am far more wary of late-night wandering now. Body ok, eyes G.O.

No, I don't walk around blindly. I have life experiences.

Coming from and living in major cities in Europe I developed a sense of being street wise. Since living in Japan I can be more relaxed about the violence but more aware of the natural disasters like earthquakes or fires. I am aware of what is happening around me and where to exit if needed.

People who act odd are often not dangerous just odd.

I'm always attentive, call me autist, but when there's a parade, I enjoy observing the crowd more than the parade itself.

For a knife attack in Japan, I don't.

I am a little bit more paranoid though when I read about a person being pushed off a train platform.

I grew up in crazy and dangerous (but also extremely fun) New York City in the 1970s and that experience has me paying attention to and not trusting anyone from children to the elderly. I live thinking that anything can happen to anyone at anytime. Walking home late at night, Japanese are always seemingly more nervous around me and I am checking them out too. You cannot be too careful anywhere.

No, I don't walk around blindly. 

but the majority of people do - their heads down, absorbed with their phones.