I only started drinking coffee two years ago. First it was once or twice a week, then it became everyday.

About 6 months ago I started having slight muscle tremors, my doctor said it could be because of stress. I didn't tell him I started having too much coffee (nor he asked me).

But the tremors kind of increased slowly. I read on HN about some guy who had similar problem with caffeine shots. It then struck them that coffee could be the problem.

Now I rarely drink coffee and tremors are also gone.