Why does a friend sometimes not act like a friend?

I’ve known an old guy “Sam” (same age as me) who is an extrovert, a-personality and charismatic. His personality is the opposite of my personality. I also have a nervous personality, and have an “anxiety problem” (according to my doctors). Also I’m gullible.

Over the last 6 years that I’ve known Sam, we have been through a lot of extreme open ocean canoe paddling situations together with several other canoe paddlers. This closeness has allowed us to know each other well. Sam knows how to push my mental buttons to get me going out of my comfort zone to say the least. Sometimes Sam makes wild accusations (totally false). This is usually disturbing to me. I don’t like it and it shows. Nevertheless Sam seems to delight in what he calls “pulling my leg”. I ask, “Why do you push me like this? His reply is laughing and saying, “You are too serious!”.

Sam also has the gift of the gab. Talks so much I can hardly speak. Sam is definitely a people. He wears me out.

I’d say that Sam is cool to be around 80% of the time. So why do you think that that Sam thinks it’s OK to be mean to me sometimes?

Perhaps my low key easygoing nature bores him?