When we are young, we don't worry about a lot of things. As we get older, we will experience failures, disappointments, letdowns and tragedies, and they change our perspective on how we think about these things. Something we could have done carelessly and worrilessly before - but if an accident happens, those become quite conscious activities that cannot be properly enjoyed anymore the way we used to, making it hard to ever enjoy things again the way we did in the past.\\
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My example is smartphones. When I was young I had a Sony Xperia Z1 Compact, and thinking back to it makes me instinctively go "back when phones still had good, lasting batteries". Why? Well, because back then I never thought about battery life. I knew it was a thing, but I didn't worry about it at all. Even as the battery life of that thing //did// run down, I didn't really think about it at the time and just plugged it in. No care in the world! //Now// whenever I plug a phone in, I analyse how long the battery lasted, and compare it to previous battery cycles, what should be normal, how much I used the phone and for what, etc. etc., it's worrying galore. This is because I have, in the meantime, made plenty of experience with battery degradation, in phones, laptops, MP3-players, anything that runs on rechargeable batteries.\\
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Other people may apply the same kind of thinking to things like washing machines - they used to last longer. Fridges, cars, whatever. It can be applied to people as well. As soon as you start to worry about things, you won't be able to enjoy interaction with humans from the unprejudiced perspective in your past.