You can't go into it with those thoughts lol, but at the same time the biggest thing I try to stress to people when they're thinking about acid is the people you're around, and the actual environment you're in. Nature can never do you wrong, trust me!
Also, while in your trip, you can navigate it. It might sound unrealistic, but it couldn't be more true. At least for me it was, if I'm having a bad thought, it's easily avoided by thinking of something else, or just letting someone know so they change the thoughts for you.
Acid is a beautiful thing, it opened my mind to things I never could imagine, even if someone described it to me lol. It's an experience that I wish everyone could have. Shrooms always made me laugh and enjoy myself on another level, whereas acid always took me places in my mind. I love them though, I would have been a hippie if I was born in that era.