I am sure there are mistakes. Could you please tell me where they are ?
"Sometimes we are losing too much time to think about people who don't think to us not even one second".

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How about this:

'Sometimes we waste time thinking about people who don't even think about us for a second.'

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Thank you. It is good to know it.

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...or with punctuation:

'Sometimes, we waste time thinking about people who don't even think about us, for a second.'

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The prepositions that follow "think" are usually "about" and "of". Not "to".