What's wrong with doing a carrier rush?

Just had a 2 on 2 coop game vs hard ai with a friend of mine. It was ZnP(me) vs TnP. At first, I transitioned to 2-gate and we both defended the center with some minor hit n run micro with my few stalkers + his zergling swarm.

Having fended off the inital AI attack, I then tried to transition to a couple of void rays and tried to do in the zerg, but had to retreat since he already had some mutas and hydras when my Void ray arrived(yeah i'm slow sorry about that).

Anyway, I didn't know what to do after mid-game so I just did what I usually did in SC1: mass carriers. There I was sitting with lots a gold so I just built some proxy bases + 2 more gateways(for continuous supply of stalkers) and just spammed the carriers.

We eventually won the game but now I heard he's complaining I did a carrier rush. What's wrong with doing a carrier rush? I know I could've gone immortals and colossi but I still haven't got used to the BO for those and carriers were a bit 'easier' to transition after void rays. What did I do wrong?

First off, let me start by saying: There is nothing wrong with Carriers.

Though they haven't seen the same revival that Battle Cruisers have under Terran, Carriers remain a very viable late game unit. Even in a world of "Hard Counters" Carriers do an enormous amount of damage and require very micro to beat. For players invested in heavy ground forces Carriers make a very nice addition and force an opponent to "split" his strategy between disparate units. While many people might point out the effectiveness of Vikings, Void Rays and Corruptors against Carriers, you have to keep in mind: All those units are effective against Colossus and those still make many appearances.

The largest problem with Carriers is they are often overshadowed by Void Rays. Void Rays are a very powerful unit against Armored and once charged. By comparison Carriers have neither of those drawbacks and are only more expensive. Finally, while many people will tell you that Carriers are countered by good micro, this is also true for EVERY OTHER UNIT IN THE GAME. The only difference is that Carriers are more effective against bad micro.

Now you discussed Carrier Rushes, and what I am about to say could apply to any type of rush: A Rush is not necessarily a Cheese. You should not use the term Rush pejoratively.

Technically going 2 Gate is a kind of rush. A rush just means quickly getting to something, and is frequently used as a technique to counter more Macro intensive play. Since many players play a Macro intensive play, a rush is a very good strategy. The trap your friend is falling into is that he is surprised by the sudden force and is using the term rush to dismiss it.

"Oh you didn't really work for that, you just rushed it."

This is actually a mistake in terminology. What he means to say is: you're doing an all in gamble on Carriers and if they failed you'd be screwed.

All in play is often considered boarder line cheesy because you are often unable to recover. However, since the goal is to do more damage to your opponent than you are doing to yourself, a very good timing all in, is an incredible effective strategy. Since an all in does not rely on lucky or bad play from your opponent, it is not nearly as cheesy as something like a proxy Rax. As a result, most All Ins are more moves of desperation than cheese.

Whether or not you consider All In play to be cheesy, a Rush is not by definition a cheese and you shouldn't feel bad about it. Even if you had Rushed Carriers (which it sounds you hadn't), that would be an interesting new build, not some sort of gambit play. So build them at your leisure.

And do try to enjoy yourself while playing Starcraft 2.

Looks like your question is basically "what's wrong with mass carriers / carrier rush". Well first of all, what you did was not a rush in any form, since you describe a middle/late game action.

Secondly, there's nothing wrong with mass carriers, it's just that many consider carriers to be underpowered considering their price. Once you get a sufficient number of carriers, though, their damage output becomes incredible - so in large numbers they are a very viable option.

I see no reason why your friend should complain about what you did. First of all, he should tell you that he does not like the carrier idea ingame, right when you started building them. Secondly, if your mass carrier strategy worked and your team won it was not probably a bad idea, was it?

One thing i observed while playing 3v3 or 4v4 that carriers are actually used quite a lot. This might not be true for higher leagues (i play gold leagues in 3v3 and 4v4). Usually in 4v4 we do an early push with tier1 units (lings, marines, zealots) and then our protoss player transitions to carriers while the rest of the team fends of any incoming attacks. One of the terran players backs them up with a few vikings and thats it. I'm not saying this is the best strategy, but works good in some cases.

A Carrier rush is pretty much impossible in my opinion. Carriers take so much tech and preparation that by the time you have a decent number of them (since they're useless alone), no reasonable person can say that you rushed.