Oh no...

For example, they can spawn mobs, summon items, change weather conditions or even initiate a minigame.

To undo a command, the first thing you need to do is locate the command block that contains it. Then you can use the "/undo" command to revert back to the game state before the command was executed.

... while "/weather" lets you change the environment from rain to snow.

Building a house in Minecraft requires the use of several different commands. Firstly, you'll need to use "/fill" to quickly and easily create walls, floors, and other structures. After that, you'll want to make use of "/clone" so that you can copy and paste specific parts of your house without having to build them all from scratch. Finally, you'll use "/summon" to spawn in furniture and other decorative items. With these four commands, any player can have a beautiful home built in no time!

The 4th command is a secret well kept...

The "/noai" command in Minecraft can be extremely useful when trying to create a more challenging and realistic gaming experience. This command prevents any artificially intelligent entities, such as zombies and creepers, from attacking or following the Player.

Ah, yes, more challenge by literally making zombies be braindead.