It’s correct either way, but the meaning is different. Google has no way of knowing which aspect you have in mind. Did this thought arise as an event on a particular occasion, or did you habitually have this thought? Was this thought present in your mind during a period of time *the length of which is irrelevant* to you now, so that it is only background information, or was having the thought at a specific time relevant? Choice of aspect does not require any so-called “triggers”, any more than in English — we can say “I eat” or “I’m eating”, depending on the aspect we have in mind, not some sort of trigger words. By the way, we *can* say “quise ir”, but the English translation would most often be “I tried to go” rather than “I wanted to go.” This change of verbs in the English translation is as much a peculiarity of English as of Spanish. You may like my popular mini-article that touches on the theme of right versus wrong in language study: Are YOU a NON-BINARY language learner? https://www.italki.com/discussion/205633

Thanks, Rafa!

If you use "pensaba", you´re doing a description of a past event, and it can also be used as a present tense with a courtesy connotation. If you use "pensé", you´re highlighting that the event is completely over and there is no effect on the present.