At least, that is what was written on the love-comedy novel that I was reading before I died.
Therefore, for sure, I will knock before opening the door.
It’s not important that it is my own room. Since there are people in it, knocking is a must.
It’s as essential as a baseball player undergoing grueling training for the National Tournament.
I'll knock it 100 times, hit on the door, and hit it.[5]