Depends on the context.
- My meeting? Right on time.
- Team meeting? On time.
- A meeting I knew about, was on my calendar, and requires my expertise? Right on time, but a lower priority.
- Something is broken and we're grouping up? Right on time.
- A meeting on my calendar that I don't really need to be in? 2-3 minutes after, I'll finish what I'm currently engaged in or get to a stopping point.
- A meeting I've been invited to with no additional context? 2-5 minutes late.
- A meeting I was invited to with no communication/context that is before/after my normal working hours? If I remember and I'm bored.
- A meeting I was inviting a to outside of my working hours and will start before I come online? Forget about it.
I work for a global corpo, so the last two happen quite a bit. Time is money friend.
Shell colors change the game really. I did this at work; when I'm on the admin server my prompt is rainbow, other servers black (I use a solarized light terminal). It has saved me so many times.