Never had a problem in my single player games.
Basically your game works like this: Your CPU calculates EVERYTHING it needs to calculate each passthrough(tick) and if the time it takes is less than 1/20th of a second you are probably fine.
So if you do some stupid tricks that use up enormous amounts of time to calculate each tick, but generally got nothing else going on, then sure go ahead. But later down the line you might add some machines, automation, magic mods etc. and suddenly all the the little additions have added up with your "chicken hole of stupidity" and gone over the normal tick time. And now you got "lag".
Yeah, but multiplayer multiplies the burden by the amount of players doing that thing.
Yeah, on servers you are most likely to be running much closer to the tick time limit just from all the people building normal stuff, a lot of overcomplicated, oversized and probably a number of similar stupid contraptions.
I have seen both server and client(those in range of it) performances brought to their knees more times than I can count on my hands by people stuffing too many animals in their pens, villagers breeding out of control in a house or similar.