sugar abuser

1.
A person or colleague at work who puts an extreme amount of sugar in his/her coffee from the canteen without thinking about other employees who want sugar in their coffee too.

2.
A person or colleague at work who throws sugar sticks to their colleagues without saying something.

He is always putting so much sugar in his coffee, he is a real sugar abuser.

My colleague at the other side of the table is a sugar abuser because he throws sugar sticks at me.