So i'm doing a quest for the ambassador and i'm idolized by the NCR and i'm waiting for the guy to come back to his office by standing outside of it and using the wait function then suddenly an NCR MP comes up to me and talks to me like i'm some scumbag and all the NCR turn hostile to me and attack me for no reason at all and i lose a ton of progress because of it. I don't feel like playing anymore since something always breaks or freezes or crashes or just don't wanna work.
50 bucks out of my pocket.

What quest are you doing and what armor are you wearing?

This has NEVER happened to me because of a bug or glitch but it HAS happened because I went into the wrong area or was wearing, like, Powder Ganger armor (near Primm... that svcked).

This happened to me a few times but i think i walked near an off-limits area?

happens randomly when you work too much for mr house and you receive the quest "don't tread the bear" the best thing you can do in this game is kill NCRs, imo.

NCR embassy doing that quest were you have to deal with pacer. i talked to the king but i had already used my favor. so i went back to the embassy like i was told to and i waited for the guy and suddenly all the NCR troopers attack me. i had my leather armor on the one i had been wearing for most of the game.

Also as soon as that quest popped about don't tread ont he bear i stopped doing Mr. Houses quests all together.

this happened to me in the NCR embassy while getting that quest, but before I had started it. Maybe because I had already talked to the King? I don't know. I was idolized by NCR and had super good karma. No reason why they attacked me. I re-loaded an earlier save, did a few more quests before coming back to the embassy this time, everything went smoothly. Clueless as to why.

I do know going into or too close to a restricted area can trigger this, but that's not what's happening at the embassy, I don't think. I got too close to the monorail at Camp McCaran, for example, and they MPs guarding the door came at me. I had no idea why until I walked more slowly the next time and heard one of them warn me not to come closer. The first time I was running full speed and I guess I got too close before I even heard anything.

Do you have ED-E with you? It can sometimes randomly turn the NCR hostile, especially around named npc’s.

It’s easy to get around, just have it wait or at least save before you approach them.

I've seen it happen with ED-E too perhaps he is spewing Enclave propaganda while you aren't looking

I've had both EDE and Rex trigger combat with friendlies. I also think that Veronica may have as well, but couldn't confirm in the melee that ensued....perhaps it was coincidence that someone happened to say "What the f*&$ you looking at, Lady?" just before she and Rex reduced the inhabitants to jam....

same happened to me. i was idolized by ncr. then started the kings quest and never realized what i was getting into. completed the quest now and have ncr infamy. so its not definite if that will affect my other current quests working for them? i wanted a good relationship with them and didn't mean to mess it up

As far as I know, get used to it! You know what's going to happen at the end! They seem to randomely attack you in certain places. Adds suspicion of them in the game. Like why the hell are there a bunch of wannabe NCRs running around bothering the public in Freeside? ... and why are they asking me around town if I am an "NCR citizen", when the hell was Las Vegas renamed NCR? BUAHAHAHAH! Yah right! The game even admits that you've done something good when you get rid of those wannabes. Why did those suspicious NCRs start shooting at me near the Vegas station monorail? God knows, but they may be responsiblle for it getting bombed, but thank God I saved the day. @ the end of the game, I had to take responsibility and was going to help both the House and the NCR... but the NCR wanted complete power. Why? Mr. House was very nice, especially for his nice "finess" comment about me. Anyways, grandma Lily had full right to defend herself from the NCR "prospectors" shooting at her. For that reason Mr. King trusted his K9 with her, and they made a great combo together! That was a blast! I wish I could shoot the crap out of those NCR drooling over the last remaining [censored]s of The Strip outside Gammorah... but prosttutes also are human and deserve a chance in changing themselves for the better. I wouldn't be surprised if Mr. King and them kill each other in a fight.... because damn they really needed our help once against them... and on top of that they were a cinch! They should make a robocop sequel to this game!