I meant that you can die from the direct physical effects (as in just having it in your system will kill you) of drugs like heroin, cocaine, caffeine, alcohol, &c. but drugs like cannabis can't be consumed fast enough to kill you (or you'd have to do it on purpose by injecting thc extract straight to your veins or something like that). It's the same with lsd actually, the lethal dose is 0.2-1mg/kg, the usual dose is 100-200ug. So a 75kg adult would need to consume 15mg of lsd = 15000ug = 150 normal sized blotters, which would cost you at least 150*5$, no way to accidentally OD on that.

But yeah if you're unstable in the first place, one too many beer or one to many joint and you'll do stupid shit. Anyway, always research, buy from renown sources, test your drugs (kits are available on amazon, ebay, &c.), do it in a safe environment with people you trust, don't use drugs when depressed or suicidal.