I've fallen into this exact trap when I played the HD remaster of Suikoden 1&2 a few months ago. The games still hold up pretty well but are a bit too dated to my taste to have more than a single playthrough, so I followed guides to get the perfect ending, which involves recruiting all 108 characters into your army.
At first I was just looking at a very light guide that told me which characters were missable and approximately when to get them. Then I got impatient and looked up their location and recruitment conditions. And then I ended up following a complete walkthrough step by step to make sure I wasn't making any mistake.
That completely took the fun out of the games and I burnt out halfway through the second one.