I spend a lot of time hanging around in cafés. Sometimes with friends, sometimes with a book or some unwritten letters. I find that although you do have to pay a bit for it, sitting in a café is almost always more satisfying than sitting around in your own home. For one thing, you left the house! Hey, you're a busy person with places to be! Haha, I'm so lame, but I actually do find myself thinking this. But affirmation of the exciting nature of your own life is not the best bit about being in public. That would be the presence of the general public, and specifically watching them and making silent judgements about them. You might see an attractive member of the interesting sex, somebody with amusing hair or clothes, or hear someone speaking a foreign language that you can't guess what it is. Which you probably won't in your living room, unless you live with a fit Armenian who wears clown trousers.
I also work better when I think someone's watching me, which is why a café is a good place for letter-writing and, when I was a student, for taking notes and so forth. Even though the other people in the café really don't care whether you are doing that thing you're supposed to be doing, the desire to be seen to be working is strong enough to make me work. I do realise I sort of just endorsed George Orwell's vision of a dystopian future. But in my scenario, you can choose to go home and hide in your room watching YouTube videos for hours if you so wish. I also take a guilty pleasure in reading in public. I know you're not meant to read to show off, and this is honestly way down on the list of reasons that I read, but it is kind of gratifying to sit with the title nice and visible if you are reading something a bit intellectual. I mean, the other clientele almost certainly haven't noticed and would not be impressed by your French novel if they did. But you never know! Possibly someone will see what you are reading and comment on it, and you will have a long conversation and bond over your love of To the Lighthouse and be best friends forever. This has not happened to me yet.
The coffee is also generally better, and you don't have to make it yourself or wash up your mug afterwards. And you can get a nice biscuit with it. The only bad thing is that, outside of the UK in general and in Iceland especially, you will simply not be able to get a proper cup of tea. Which is a shame, because tea is not so caffeinated or strongly-flavoured and therefore better suited for mass-consumption over a long period. It is frowned upon to take your own Yorkshire teabag to a café and ask for a cup of boiling water. Don't do that.
So if you're ever in Reykjavík and looking to spend some time hanging around in a café (which you may well want to do, since it will probably be raining and you'll already have seen Hallgrímskirkja and the Ráðhús and that boaty statue by the sea), here are a few I have enjoyed.
Kaffitár: Really good coffee. Usually there is a choice of two and there are labels on the machines telling you where the beans are from. One time I had a coffee there that was labelled "cup of excellence". The cakes are good as well, and they sell world-music CDs with titles that make me laugh - my favourite is "Jewish Odyssey". Kaffitár is right where Laugavegur turns into Bankastræti, so if you sit up on the stools by the window there are fantastic people-watching opportunities. You will see all the yellow trousers and unicyclists from here, I guarantee. Once I saw a few members of Sigur Rós getting some coffee here, so you should know it is rock-star endorsed. When it rains a lot, there is a puddle just inside the door. They should probably fix that.
Kaffivagninn: This is way out by the harbour, so probably not all that suitable if you are wandering round 101. But I've been here a few times and the pancakes are really good. You won't see tourists here - it is a fishermen café. No jokes, it is full of men with beards and heavy-knit woollen jumpers discussing their catches.
Tíu dropar: Because it's on Laugavegur, this place can be quite good for people-watching, but only if you position yourself carefully. It is below street-level, so you can find yourself trying to judge people on their lower legs, which is not as much fun. Nice pancakes. I would probably go here for lunch rather than just to sit around reading, though.
Hemmi og Valdi: Good sofas and a big window onto Laugavegur. But the coffee cups are kind of tiny and I'm not sure whether they have a refill policy? Most cafés in Reykjavík you get a cup, then help yourself from a caffetiere as many times as you can handle. If they do that here (genuinely don't remember) then I should go more often. It's a nice pub in the evenings as well, as long as they don't have the ubiquitous "local DJ" in.
Kofi Tómasar frænda: I like the music in here. Because I think it's usually just some staff member's iPod on shuffle, so you get some interesting juxtapositions. There is no attempt to find a mood and stick with it. Once I heard Jeff Buckley's version of Hallelujah directly followed by Mambo Number 5. This place doesn't do the refill thing. What they do is give you a thermos containing more coffee than you could drink and survive. Well, I think maybe I could physically finish one of them, but I wouldn't feel very well. My experience with the cakes in here is that they are about 60% icing. Which is nice, but also slightly damaging. If you want to make yourself a bit ill on caffeine and sugar, this is the place to come. I've made this café sound really off-putting - it's actually one of my favourites! You should go. The name is "Uncle Tom's Cabin" in Icelandic, and it's also a bar in the evenings.
Eymundsson: This is a book shop on Austurstræti, but if it is mad sunny, there is a café on the top floor which you should go to. You can sit out on the roof, which is all sheltered from the wind, and try to get a tan. I had the best cup of tea that I've bought in Reykjavík here. Unfortunately, this is not saying much.
Babalú: I saved this one until last, because it is hands down my favourite. If you just want a quick coffee and a chat, any of the others would do just as well, but if you're looking to settle in for the afternoon this is the place to be. I love pretty much everything about it. It feels like the living room of someone who is quite a lot cooler and more interesting than you, but not in an intimidating way. They have board games. The mugs are eclectic, and proper size. You can't watch out the window (although you can look down on Skólavörðustígur from the balcony in good weather), but it doesn't really matter because there are always loads of hipsters and tourists to watch inside. I really like the biscuits as well. Yep, Babalú is a winner.