Hmm... Well, I could smoke the joint, not smoke the joint but still see the movie with them, or I could not go at all.
If I decide to smoke, it would be fun and my friends might think I was cool, but I could get caught. I could also get caught even if I don't smoke it but still go. Marijuana is illegal and they would likely smell it on me. On the other hand, I really want to see this movie with my friends, which I can only do if I go. If I don't go I won't be able to see the movie, but I will have no chance of getting caught.
What's influencing me internally is my impulses and wanting to see the movie. Externally I'm being influenced by my friends and the law.
Sure, I'll do it, too.
I think I am going to smoke the joint, even though this is an unhealthy choice because marijuana is illegal, causes poor coordination, and poor judgement, so we could easily get caught.