Allow me to share an exchange I’ve had with new players countless of times, both at our locals and online:
“I play this backup!”
“… you can’t, you don’t have the right color, and that’s n-”
“But I don’t need the right color for backups???”
“You don’t, but that’s not a backup, that’s a coun-”
“But the guy who taught me said if it has this icon, it’s a backup???”
And that’s usually the part where I let out a deep sigh before circling all the way back to explain the counter icon, the backup keyword ability, why activating an ability of a card in your hand is not the same thing as playing a card and why the resolution zone exists but also isn’t actually there.