My mate went to Amsterdam with his girlfriend last year, it was a bit of a traumatic time, he had been out on the Saturday before he went (2 days before) with his mate, who was killed when they were out on their motorbikes.
Regardless, he went anyway as he didnt want to let his girlfriend down, they were staying right at the train station near the red light district, his girlfriend was tired, at 10pm he went out for a few drinks, he went into a bar, then the next thing he knew he was walking about 5 miles away from where he was, his feet all blistered, and it was 6am.
To this day he still has no idea what happened, he presumes someone slipped something in his drink, or he took something by his own accord, but has no recollection of it.
Anyway, time can go missing easily in Amsterdam!