No kidding. There's no debugger. You can't just set a breakpoint and see what's going on under the hood. It's more like playing Russian roulette and hoping you don't bring the whole network down.

It's messing with the wiring while it's still hot and there often isn't a better way to do it.

We were all into networking when I was young. Had to make Lan parties and UT servers work somehow.

Everyone still ended up working factory / distribution jobs lol.

Me too, but it didn’t really exist when I was 14.

Hmm...that one's probably around 150 gently used.

He's probably using cloud services, makes sense, why build out infra he'll have to manage 365 when he basically needs it 2 months a year?

Aha, that's why I never get what I want for Christmas: classic ASP.

"there"

LAG are aggregated interfaces and they can indeed be used to prevent (some) layer 2 loops. LAG as in Link Aggregation Group)

Using 2 non-LAG interfaces between the same 2 devices creates a loop.
In the case of a loop, if you're running spanning tree, one of these interface will be blocking instead of forwarding, preventing the loop, but also percentile the use of this interface until the topology changes (ie: the current one goes down).
If you're not running spanning tree for some reason, then both interface will chug along, oblivious to the fact that there's a loop and broadcast packets will indeed keep being flooded on one and received on the other, again flooded, etc. creating a broadcast storm and impacting performance of the whole layer 2 domain and possibly even crashing devices.

A LAG more or less means the interfaces in the group behave as one big (aggregated) interface.
LAG also means you can push traffic on both interfaces for more bandwidth.

Source: ~~Network engineer~~ Internet plumber

It doesn't.

The assumption is that they're creating a high bandwidth trunk interface to the L3 switch/router, so if they forget to create an aggregate it'll be two independent interfaces and will down the network (or a port will auto down itself with STP, MSTP, etc. but that's not as funny)