I haven't washed my coffee cup in over 5 years.
Why don't you wash your coffee cup ever? A lot of people think they'd get ill if they do so.
It's not true, because it's possible for others to get illness but it's not the case with me, i'll be fine.
You're being overconfident. It's disgusting to keep using unwashed cup. It'll definitely hurt your health.
I'm sure everything will be fine and i'm proud of being a microbe magnet
You're going to get fall sick eventually. You need to research on  such unhygienic practices , i'm sure that will open your eyes.