Marijuana in my experience does not effect ambition at all. It really depends on what kind of job you have and what you're doing. If you do creative work like blogging on Steemit I really doubt marijuana has a negative effect, in fact it could make you more productive and inspired because bloggers have to be in a different state of mind.
On the other hand if you have some kind of important job where lives are at stake, like a surgeon, or trying to run a new business which you are just starting, in that case every decision is critical and marijuana might not help when making critical decisions.
In the end, it depends on what you're doing and why, but I've never experienced any motivational issues and to be honest, it's also possible to be too motivated. People who are too motivated can find themselves in all sorts of trouble which they could avoid if they just stay home and smoke weed.
I think on a deeper level you're right, speaking for myself what you say does ring true and at times in the past I have motivated myself regardless of my marijuana consumption.
However recently, if I have realllly strong hashish, I find it hard to write; though that could be because, I'm smoking it to mask the fact I have writer's block!
:-D
Cg
You can always review the experience of the strong hashish.
Well after replying to you, I went and smoked a fairly strong one and wrote what I believe to be a cracking article :-) Hopefully later when I'm not so high and I return to edit, I'm still thinking the same thing! :-D
Cg