I think the word "stupid" is a loaded word for many people, so for the most part, it's best to just not use it.
I rarely ever use it, except with the people i'm close to and who understand where i'm coming from when i do say it, aka. those people who i know exactly how they will react to it...
Although, if i disagree with something... i think there are much more eloquent words to use than 'stupid.' I usually just say ... "i don't agree with you on that... for (insert reason here)" And that typically comes off nicely but i still get my point across.
but hehe, it's been a long time since someone's said "that's stupid" to me
But i wouldn't really care, but i would ask for a reason as to Why they thought something i was saying was stupid.
Also... it's not so much the words that we use... it's the intent that we use them with.
sweetpea