It's pretty much impossible to OD on weed. It just won't happen. You have no hangovers. I love weed. You can't go wrong with it.

But personally, and I'm speaking only for myself, but yes.. I think that at a couple times in my life I have gotten 'too high.' It was always when I smoked A LOT of kb, mainly an indica strain (an 1/8 between 2 of us one night). It wasn't a good high, and that's tough to say because highs are always great for me. But I smoked so much of this potent shit, I got extremely lightheaded and dizzy to the point I had to lay down. My heart felt like it was going to pound out of my chest, I started sweating and getting paranoid, and I really felt like I was going to stop breathing because my breathing was so shallow, but yet my heart was pounding away. It sucked. But I was alright. Just drank some water, layed down for a while, and those feelings went away. That experience hasn't deterred me from toking away!

That's only happened 2-3 times outta the countless times I've been high.