Quote Originally Posted by kgcole View Post
Question 2. If your final version is “I was sitting at my desk. I was playing a game” how would you describe “I sat at my desk. I played a game.” Can the misuse of the tense be called a rude mistake or is it the way people often say that? Can this with the Past Simple be said by your neighbor, a bank clerk, your president or a teenager chatting in a bus? I would like to feel the degree of mistake.

I wouldn’t describe the misuse as rude, but simply unsophisticated. I would describe both ways that you wrote that as not being fluent or comfortable with English. You could say it to anyone under any circumstance and not be considered rude, and be understood, but you would be identified as a foreigner and someone not fluent in English. It’s a matter of fluency only.
You could also state that beginning the sentence with 'I' again so soon is unnecessary. The pronoun 'I' was already introduced. Explaining it in terms of flow is okay, though.

Simply changing the sentence into one by adding or introducing a grammatical conjunction, and, delivers a more concise sentence that achieves this flow. Efficiency!

"I sat at my desk and played a game."