Weed is weird and seems to affect people differently. Some people seem to have life problems caused or made worse by smoking, while others I know smoke daily with no problems and are extremely successful and diligent. Basically, anxiety around drugs is definitely not unwarrented. Weed can be harmful no matter what people say, even if sometimes it's not.

As far as feeling like "you", well, I think much of the point is to not feel like "you". At least to some degree. I think the way an individual feels about being made to feel unlike yourself is subjective. It also depends on the substance you take - you definitly aren't you when you drink heavily for instance, but being drunk will mean you probably won't be too anxious about it. With weed this can feel waaay more uncomfortable since weed can open you up to fucking massive anxiety.

As far as the dude weed stuff goes, stoners act like that because weed makes surface level aesthetic stuff feel profound, and makes you want to share your observation. That's really it and that's what happened in digis weed vids.