I wouldn't say any of my friendships are intense, that kind of intensity only ever manifests in romantic relationships for me. However, I get bored or I guess fed up with friends, usually only new friends, and just drop them for a long period of time of permanently. I feel like if they don't bother trying to contact me first often enough then they don't matter enough for me to waste my time on them. Or I just get tired of drama. I've had friends who endlessly complained about everything in their lives and tried to get comfort from me when I was way worse off than they were. I think that bothers me more than anything else, it's the reason I've ended several friendships anyway.