I've often been told, "You overthink things," but so what? I always think. After all, "Man is a thinking reed," so it's natural to think. There's no such thing as overthinking.
I just "think more [than others]".
Empty your mind and take a deep breath! Even for things like that, people think and then take action. If we don't accept "thinking" in a positive light, various things are going to end up messed up.
Now, where does the idea that overthinking = bad come from? I think it probably depends on the matter you are thinking about. I once "thought" about that mechanism.
Simply put, it seems that the human brain prefers to keep things it cannot solve inside the mind. For example, pleasant things quickly fade from the brain, whereas the brain springs into action regarding unpleasant things, wondering what to do to resolve the situation. That is true even for things that happened in the past and can no longer be helped now. For instance, suppose you are dealing with someone at work whose values are completely different, and you pry into their background, analyze them every which way, and brood over it, thinking, "Ah, so that's why I don't get along with that person." (I've seen someone brooding like that in the past.) However, even if you reach a conclusion based on your own theory, nothing can be done about it. Let's stop wasting brain energy on things that won't change.
Therefore, based on this characteristic of the human brain, I vaguely think—drawing on my own experience—that it might be good to pay attention to the subjects you think about. The subjects to think about are... well, I think it might be good to concentrate on things that seem a bit difficult at first glance, but can be materialized and are likely to bring about change.
For example (instead of thinking about some incomprehensible person at work), "I want to live in Morocco!"... Doesn't just saying this make you feel excited? It gets you excited and you can't stop thinking. Ah, am I the only one who gets excited by stuff like this?! ...Haha
Because, you know, if you can materialize something through your own thoughts, anything is fun. I think that I want to think things through thoroughly for the rest of my life. Overthinking is not bad at all, because I'm just thinking a lot.
"Quantity" is good. It might be good to "think" once again that the problem is "quality".