Boss tells senior dev to show junior dev how to do something. Senior dev says okay. Get back to desks - senior dev refuses to show junior dev because 'if you fuck it up, everything'll break'... How exactly is a person supposed to learn if you won't even let them observe?!

my guess is senior dev doesn't actually know and doesn't want boss or junior dev to know that. don't sweat it, you'll learn everything in time if you're interested enough. I picked up personal projects to compensate for my slow start at my current position and ensure I was adequately learning my field and it's worked out very well for both personal projects and my job. many things I've done as side projects have been useful in my work and my senior dev is glad that I've gained the knowledge to get them done without needing him to show me. but sometimes I think he's glad because secretly he doesn't remember and doesn't have the time to relearn it with everything else he has to do.

That is very bad. If he does not change his attitude escalate to management.
When you are senior do the right thing.

@mags24 but part of the job is to be trained, or else you never lose junior status. "You dont know how to do it so ill do it" gets no one anywhere, and to boot hes disobeying the higher up. You shouldnt have to learn your job outside of work its supposed to be provided.

right, that's ideal but what senior dev has time to show a junior dev everything AND get their work done AND have a semi-normal outside work life? IMO programming requires a passion to self-learn despite what your seniors do or don't teach you. If you don't want to learn badly enough to make a way instead of just mope that no one's teaching you it's going to take a really long time to get out of junior status. Fine, go to the boss and tell him what senior dev did but you are more likely to piss off senior dev enough to get him to tell boss it's you or him than you are to get him to actually help. Better still would be to find out how to do the same thing from somewhere else and nonchalantly show senior dev that you know how for next time.

Hes not showing him everything, just that 1 thing, and he couldn't even do that cause his ego makes him think all juniors are fuck ups, hes just being a dick

but a dick he has to work under so he should either tread carefully or find another job. not likely boss is going to boot senior dev for a junior. what did he not want to teach you, OP?

@mags24 @Matthewb *she...
And it was how to set redirects... I've looked at it since (because, despite my junior status, I do know where these are done) and it doesn't seem to have been that complicated...
Also: considering the 'I have nothing to do today' statement made mere moments before the refusal, I'd say it's not because he didn't have time to show me.
I have had some issues with this senior dev - there are three here - but this one doesn't like to show or help me, he just does it himself. The other guys will sit beside me and show me, or if it's super complicated/they have time constraints, will let me observe.
The bosses do know that he's like that, and have told him to be more accomodating when we have the time.

Oh, and FYI - I'm fully self-taught, only been doing dev full-time for 6months, and very rarely do I ask the seniors for help/to demonstrate something. Maybe they resent that - maybe they think because they've done a Bachelors degree that I should be more subservient, but that's not how I roll. I learn better by doing, so that's what I do - I test, I try, I DO, until I've learned.

@pyrotazz
as a fellow she, I want to tell you to avoid letting your gender cloud the argument. you'll get called a he a lot in this field. you'll have to look past it and stay focused on the work. if you let your gender play a prominent role in your current position I wouldn't be surprised if your senior dev does too, including not feeling confident in your ability to take on what seems like a simple task. it's shitty, but it's damn true. We can be all things feminine outside of work: wear skirts, make babies, drink pink martinis, watch chick flicks, whatever your girl heart desires. But at work I've found it to be way more productive to be as gender-neutral as possible in all the things. And this is about 50x as applicable if you are an attractive female. play it down or suffer in this field, I've found. guys don't do well thinking concurrently with both heads ;)

@mags24 gosh - you're a bit serious aren't you? It's my rant - I'm allowed to correct the misconception of my gender if I so well please.
I've never let my gender define me. Before this I worked in a freight shed, driving forklifts, lifting kegs and being generally hardcore. I am the opposite of feminine. The guys here know better - they're in an office where they're outnumbered 2:1, they'd get slaughtered.
Maybe you should stop making assumptions about the motivations of people?

if you feel the need to correct in an otherwise an anonymous environment you ARE asking to be defined by your gender. why do we need to know you are female? I wasn't trying to be serious, I was trying to pass along some experience as a female in the same field but you aren't very receptive, are you.. maybe that's senior devs prob with you?

@mags24 maybe - or maybe you're trying to place the issues you've had on to my situation, seeing issues that aren't there. Assuming, once again.
I can guarantee that my gender is not the problem. Nor is my receptiveness. This dev is like this with everyone, even the Boss. Very rigid and unwilling to help. Doesn't seem to believe anyone else can understand what he does - even his fellow senior devs.
A simple 'that sucks, fuck that' would have sufficed.

it does suck, fuck that. code on.