I stayed home because it was raining, wasn't it/didn't I?

[emsr2d2]

I mean it is a sentence and I am the doer. I know what happened. Why do would I ask someone about that what I did?

See my corrections above. Don't capitalise random words in the middle of sentences unless they're proper nouns. Don't put a space before a full stop.

1. I stayed home because it was raining, wasn't it? (I want to assure the process of confirmation that it was raining.)
2. I stayed home because it was raining, didn't I? space here (I want to assure the process of staying confirmation that I stayed home.)

Note my corrections above. Don't put a space after an opening bracket. Always put a space after a question mark (unless it's followed by a closing bracket or closing punctuation marks).

Yet, I don't see the grammatical usage need of for a question tag in both sentences.

There is no need.

 

[emsr2d2]

Question tags are rarely intended as questions. They are often a fairly meaningless conversational way of including the other speaker(s) in the conversation.

That's frequently the case when the question tag includes the word "I". Neither of these are intended as questions:

What did you do on Saturday evening?
Oh, I only went and ended up in hospital, didn't I?

How come you resigned from work?
I've bloody won the lottery, haven't I?

Sometimes, though, it's really a question, asking for confirmation.

I can't smoke in here, can I?
I've only got till Thursday to hand my assignment in, haven't I?