(((((((((((SlippingFast)))))))))))))))) welcome to PC, glad you're posting.
I have to admit, I was reading through your post and all I could think was "Wow, have you been in my head recently?"
Even if we think we're wasting someone's time, we really aren't. ESPECIALLY on a site like this where its the main purpose to listen, to ask for help and find people who understand. Might not understand entirely, but we do at least a tiny bit.
I've found that a lot of counsellors (especially strangers) dont always understand SI and the stuff behind it. Makes you feel even worse... the thing is, the behaviour is at least somewhat reasonable, it's just a way to cope. Might not be the most healthy, but it's still a way to cope.
I'm doing risky things myself. Told my counsellor about my urge to "play in traffic" as I put it ... and then some people have tried to stop me doing risky things (like that, and other stuff, not suicidal but thats what I do) ... so yeah I understand and I do it too.
I think a lot about being a failure in general... education definetely included. Maybe it would help to talk about all the crap in your head? If not IRL to someone, maybe write here?
And your post is not a pathetic rant. Like I said, I understand where you're coming from.
Be good to yourself, you are worth it. You are not a waste of time and all that other nasty stuff in your head is a bunch of lies...
And I apologize for coming across so strongly.