I was waiting for you for 3 hours
and
I waited for you for 3 hours
I don't consider Present Perfect, because I want to describe a situation that ocurred in the past and completed in the past. I doubt which tense to use,because the situation was in the past and took some time (3 hours), so, logically, I think I should use Past continuous, but I saw this sentence in Past Simple on Internet too. So, how would you explain it? I need an opinion of a Native English Speaker.