my action of liking someone's content in the past suddenly reduced their value

That probably only happened in the visual part in the front end. It can happen that the value of votes change with with Hive price and if you upvote a post it simply updates the current value.
Unless you clicked the downvote button and accidentally pissed off someone :D

The place is so complex that you just cannot be bored. So many layers that bring out different emotions. I am glad you see the positive side. It is like a Hive honeymoon :)
I am still here after 3 years...

And Splinterlands hi5! :D