For me it was 'Red Dragon'' by Thomas Harris. I read it when I was pretty young and I clearly remember that the scenes describing the murderer breaking into the house of those families gave me hard shivers. I actually had to limit the reading to daytime, because it was impossible for me to read that book in the silent of the night...
Until that point in my life I haven't thought of the possibility of some mad murderer actually breaking into my house, but after that I had some nightamers for a week
TanaFey t1_ixo71vv wrote
Stephen King's "It". I was probably too young to read it at the time.