I have the worst internet probably, not because of speed, but because of
reliability.
When it works, it's amazing; however, it would go offline for many hours at a time (down for 3-4 hours after 6 pm during an important business decision, a competitive match of CSGO, or before a major assignment deadline is not too farfetched).
I've had many, over 5 techs, visit the house over 15 times to fix it, and every time they're here, this is what they see, and tell me there's no problem. It has gotten progressively better, but the problem still persists once in a while.
So if my internet isn't the worst on GH, I really don't know what is, because reliability is probably the most important thing to me, as long as it isn't too slow.
