That would be the common “double tense” mistake. Citation does not work the same way in Japanese as in English. Whatever goes in the citation needs to be what would occur AT THE GIVEN TIME.
雨が降ったと思う。 = I think that it rained.
雨が降らないと思う。= I think that it won’t rain.
雨が降ると思った。 = I thought it would rain.
雨が降ると思わない。 = I don’t think that it will rain.
雨が降ったと思った。X This sentence is typically wrong, although it is not always wrong if you’re relaying your experience or writing a novel. Then it would mean “I thought that it rained IN THE PAST, NOT AT THE TIME I WAS THINKING.”
と quotes the thought that one has. So at that time you were thinking, that guy would be mean, not that guy was mean.