In MGS1 (PS1), at the beginging of 2nd disc, you reach indoor (after killing Sniper Wolf I think) and you are required to slide/walk with back to the wall. Unfortunately I didn't know that Snake can slide with back to the wall...so I tried everything I could think of, went back to see if I missed anything. You won't believe that I was stuck there for 2-3 months IIRC and went mad. It is only after reading a walkthrough I came to know about it. How is that for a gaming stupidity?