Onto siding with Elder McNamara and simultaneously siding with the NCR. No survival for the Brotherhood in that scenario. God damnit.

The worst decision I've made in New Vegas was killing Oliver Swanick when I first arrived in Nipton. I felt so bad after finding out what the Legion had done and the so called "Lottery" they held at the town. The man had won his life and I took it away thinking I would win some bottlecaps, I was very wrong. Additionally, Killing House is a close second as I felt very guilty after doing the deed.
As for Fallout 3, there are a ton of bad decisions I've made including helping Roy Phillips, Betty(Braun), etc. However, blowing up Megaton was my worst decision. When Dad confronted the Lone Wanderer about it, I just felt even more horrible. Keep in mind, I almost exclusively conclude my playthroughs with good or neutral outcomes as I just cannot handle being a pure scumbag.

Letting Rex come with me to a firefight. -_- I didn't know he had so little health or maybe it was just that all the raiders focused their fire on him cuz he was charging in head first. XD Next thing I know a message popped up saying he died, couldn't stand losing my canine companion.

The Worst decision I've made ?

In my first playthrough ever, I joined Caesar's Legion... enough said ! XD

Killing Gloria Van Graff before getting Gun Runner's Arsenal on the Xbox 360. Needless to say, I couldn't last without good ol' Smitty and reset a 300 hour content character.

@PROROOK363 ( I moved my post from one topic to another because I post my message on the wrong one XD )

As I said, that's a pretty big mistake XD !

@"FafnirEtherion" Yeah tell me about. About as much a mistake for anyone who tired to cross paths with me and OL' SMITTY. That cannon's a beauty I swear.

I was drunk and I don't remember, but it had something to do with deathclaws.

For me the worst decision I made for either of them was buying the games at release date. The bugs oh my god the bugs. Fallout wouldnt be as popular without mods like UFO3BFP, UFNVBFP. and UFO4BFP.

I question if Beth has a QA team sometimes... Atleast Fallout 4 they are doing open betas to QA.

Learning how to mod-now I spend more time looking for mods and learning to mod than actually playing

@Lucianhector I know that feel, bro XD !

Each time I look at something in game, I think " I should mod that " X)

my worst decision? destroy the BOS instead of join with them XD XD most of my playtrough are with NCR btw

Fo3 i havent really played much of, In FNV my worst decision was to side with the ncr almost every time my last playthrough was with ceaser and was much more rewarding.

the worst thing i did in FNV was letting oliver swanick live on my first playthrough

When I first got to Rivet City I tried to steal a rifle when all of a sudden they ALL turn hostile so I then look at my save and it was all the way back to the Museum of Tech. A very frustrating day lol