There are definitely some effects associated with marijuana that I'm not comfortable with. One of them being loss of coherence. Another is forgetfulness etc...
They're not bad enough to stop me from smoking it though. There's way too many positive effects from the drug that over-weigh the negative ones. I definitely won't smoke weed during situations where I find myself needing to take things seriously. I smoke it when I'm free, and within an environment that I feel comfortable and relaxed in.