You haven’t taken it until it is finished
And again, that means diddly squat.
Shield master doesn't care that you haven't taken it. As so as you take it, it's triggered.
You haven’t taken it until it is finished
No, you are in the process of taking the attack action if you haven’t completed it
No, you are in the process of taking the attack action if you haven’t completed it. If you are in the process of taking something the. You haven’t taken it yet
Yes. You are taking it. Oh look at Shield Master: "If you take the Attack action".
You argue as if Shield Master reads "If you took the Attack action", which is why you're wrong.
You didn’t take the attack action if you haven’t finished taking it.
No, you are in the process of taking the attack action if you haven’t completed it. If you are in the process of taking something the. You haven’t taken it yet
Take is not past tense. It's present tense. Therefore this statement (grammatically), and argument (logically) is invalid.
If you declare the attack action and never attack did you take the attack action?
Yes. I'd say you did. If I have extra attack but attack only once (either by choice or circumstances) did I actually take the Attack action?
I really don't understand why some people insist they understand the rules better than the people who professionally wrote and interpret said rules.
I mean nobody's arguing against house rules to interpret rules in a way that makes more sense for the fiction or game flow or whatever at anybody's personal table. But if you think you have greater claim on understanding and interpreting the RAW than Jeremy Crawford you're sadly mistaken.
Again, I don't think anybody's interpretation or application of the rule is wrong; there's simply RAW and then there's House Rules. You can disagree with the RAW. The entire point of House Rules are when you disagree with the rules as they are written or don't think they work as well for your own table. But there's no sense in arguing that it isn't actually RAW.