This is not an official rule, but still...

When you test something, for example how far something can reach, don't say "offscreen" or "halfway the screen". One "screen" is not a stable lenght, since resolution changes your visible area. Use "tiles" or "feet" instead.

I play with a large resolution, and my friend has a huge monitor, and it really gives him an advantage in PvP. Also I notice particle effects and light disappearing near the edges of my screen.