Before the internet most of the things we had to find out ourselves. What are some things you found in games that later became "a thing" or you have heard other people talk about in the decades since?

Here are just a few off the top of my head:

PacMan 5200
-After reaching a specific stage in the game, as long as you ate a power pellet and didn't eat a ghost, they would remain blue for the whole level. If you were careful you could avoid them and complete the level and do it again on the next level

Super Mario Bros NES
-When coming out of any pipe, hold down the A + B button until Mario lands on the ground. This will cause him to slide like he is ice skating across the ground.

Punch-Out!! NES
-When fighting Soda Poppinski, hold down to block when he goes for an uppercut. For some reason this will cause him to freeze in place. Punch him with a body blow while he is frozen and you will get a "special" star. If you press start and hit him with this special star uppercut he will be knocked down no matter how much energy he has left (even a full meter).

I'll perhaps return and type more later, just curious what things other people found in consoles, computers and arcade games back in the day...