A mistake I often see less experienced players make is that they just keep playing every Action card in their hand until they're out of actions, even when the Action cards have 0 effect. What's worse is that they keep playing those Action cards if they actually have a negative effect. Why? Well, just because they like playing strings of cards, because that's what the game is about, right? Nothing like playing 10 Villages and feeling like a boss.
Zero EffectThis is the least hurtful, but it can still be annoying for your opponents. Imagine having drawn your entire deck and still having 5 Wishing Wells. Luckily, the interface on Iso knows that you have no more cards and thus you can't wish for anything, but I wouldn't be surprised if someone got a smack in the face in real life for doing this and still wishing for stuff and acting all surprised "Oh, I don't have any cards in my deck anymore!" every single time. Still, it's not so bad to play Actions for 0 effect, it's just pretty useless. But this paragraph only serves as a step-up to negative effects.
Negative EffectWhen does playing an Action card have a negative effect? There are a couple of cases:
- They hurt yourself directly
- They hurt yourself indirectly
- They help your opponent directly
- They help your opponent indirectly
Let's deal with each case separately to give you an idea of what I mean.
1. They hurt yourself directlyNow how can playing an Action card hurt yourself directly? Well, you could play a cantrip before Menagerie drawing a copy when you had a hand of uniques, but that's not what I mean. What I mean is with a card that forces you to do stuff like Golem-ing into an Ambassador, Masquerade, Trade Post and the likes. Throne Room is similar, always weigh the risks vs. the rewards. If you have TR-TR-Lab and some risky cards still in your deck, consider just TR-ing a single Lab instead of starting off with TR-TR. It's too easy to automatically start a chain with TR-TR without thinking it through. TR-TR-Lab-Terminal leaves you with 2 Actions remaining while TR-Lab, TR-terminal leaves you with 1 action remaining. Is that one action worth the risk? I don't know, but you should think about it.
2. They hurt yourself indirectlyActions that hurt yourself indirectly have mostly to do with your next hand. An easily understood example is playing a cantrip after a chain of Hunting Parties. A typical Hunting Party deck will still have Coppers and Estates and happily skip them while searching for your good cards, leaving you with an empty draw deck and full discard. What happens when you play that cantrip? Your Coppers and Estates get shuffled into a new deck, one of which you will draw, and your Hunting Parties played this turn will miss the shuffle. Shuffle timing is very important in HP decks, play the cantrips first to not risk drawing into your discarded crap. Warehouse has a similar style. After a few Warehouses, you've discarded most of your crap, don't play that extra Warehouse just because you can and force your Curses, Estates and Coppers to make up your next two hands.
There are a lot of cards which mess with the top of your own deck, either by revealing or drawing, and can cause an unwanted reshuffle. If you played a lot of good cards this turn, they will miss that shuffle. If you have reached a certain treshold, $8 for Province or $11 for Colony, and only have 1 Buy, always consider stopping the chain as an option. Think about what's left in your deck. Try to leave $8 for the next hand as well instead of $16 for this one.
3. They help your opponent directlyReactions immediately should spring to mind when thinking about cards that help your opponent directly. Of course you don't always know whether your opponent is holding Watchtower or Trader when you're thinking about playing that Sea Hag. But again, you should think about it. Sometimes you can know in advance due to having seen the cards of your opponent with a missed Bureaucrat or Cutpurse. There are also cards which give the opponent an extra card or choice, Governor, Council Room, Vault, Bishop, etc.. I've made a costly mistake once when I needed to play 2 Governors as remodels to get the last Duchy and Province. I took the Province first, allowing my opponent to sneakily transform a $4 into the last Duchy. It was a silly mistake which could have been prevented if I hadn't played on auto pilot.
4. They help your opponent indirectlyExamples of cards that help your opponent indirectly are the ones that mess with the top of the deck. Uncertainty plays a part with Sea Hag and Swindler. Consider a game where you're trailing by more than 1 Province and you already have $8, Curses are gone, but you think "what the heck, let's play Swindler" and oops your opponent trashes a Province for a Province. It helps to know what's on top of your opponent's deck, Oracle, Spy, Scrying Pool etc help, but even if you don't know it's good to pause for a second. The information you have about the top of their deck is not 0. Because Dominion is a game of incomplete information, the trick is to make the best decision based on the little information you do have. Oftentimes you can prevent looking like a fool if you think about the order you want to play your cards in. After a couple of Rabbles your opponent has 2 Provinces on top and then you play a Tribute for kicks and giggles (you don't need the benefit of 2 cards), your opponent will be very grateful!
If you're playing at a high level it's important to not give your opponent more information than what's absolutely necessary. Playing every Copper one at a time isn't what I'm talking about. Imagine a game with Governors where you just played your single $4 card, a dead Sea Hag, for no real reason other than boredom and maybe discarding a good card. Your opponent can now safely use Governor to remodel knowing that you can't pick up a Duchy this turn.
What to take away from thisI've shown a couple of ways for Action cards to either hurt you or help your opponent. Now I'm not trying to scare you into never buying or playing some cards or doubting every simple situation, I just urge you to weigh the risks versus the rewards. Don't just play your Action cards simply because you have actions left over. Dominion is a highly situational game where solid tactics can sway close games in your favor. Don't just consider which cards to play, always consider if it's even worth playing them at all.