I started changing my behavior already at the beginning of March. First step was cancelling my birthday celebration.

Then I asked at my job about possibility of working from home. I was probably seen as too paranoid, but my boss agreed, temporarily. A few weeks later, working from home became an official company policy. During summer it became optional, but I stayed at home. Now working from home is mandatory again. As a consequence of working from home we had no business trips and almost no teambuilding activities, and I ignored the few that happened.

As a consequence of working from home, I stopped eating in restaurants. Most of the days I cook a meal for my family. My cooking skills improved.

I almost completely stopped using mass transit. Now when I want to get somewhere, the first step is looking up on the map how much time it takes by foot. If it is less than 30 minutes, I go by foot. I was surprised to learn (in near-mode) how many places are within this distance. It helps that I live near the center of the city.

Our vacation choices also changed a bit; now we only accept a subset of choices we would have accepted in the past. No big hotel; preferably a separate house. No eating inside.

During the spring the kindergarten was closed. During the summer it was open. Now in the autumn it is still open but we stopped sending our children there.

During the spring we experimented with having food delivered to home. We also rubbed everything we bought with alcohol to disinfect. But after a few months I stopped doing this, because it was too inconvenient.

I am generally introverted, but now I meet people outside my family less frequently than usual, because I don't have lunch outside, I don't visit other people at their homes nor invite them to our home, and I don't attend Less Wrong meetups.

In March-May I didn't interact with anyone in-person outside of my housemates, who were doing the same. One of us went shopping, about once a month, and we made an effort to get most things delivered. We quarantined the mail for 3 days before opening it, etc. We were pretty intense.

Now, we don't quarantine the mail at all (not really worried about surface transmission in general), and we do "go into work" but in our case it's a huge building and 90% of the time we're only in the same room as people in our germ pod. We also frequently host some small gatherings now but it's always outdoors, with some rare exceptions for like a 10-minute tour of our building for just a few people. We shop every 10 days or so, and have added a few "frivolous" trips to the hardware store.

We get burritos several times a week from our favorite food cart, but otherwise prepare all of our own meals now - we used to eat at restaurants 6 or 7 times a week, but indoor and patio dining are still a no-go for us.

I don't expect we'll revert to normal-ish behavior until we have a widespread vaccine, treatment improves significantly, or some other unforeseen turn of events...

Covid has turned out to be something like 5x less severe IFR than many of us were worried about in March, but it still seems bad enough to take a lot of precaution. My personal risk of dying is super low - I'm healthy and 31. However, I'm still being really cautious because of the not-well-understood long-term effects. SARS was really nasty on that front. What evidence convinced you that's not a big deal? If you don't already have evidence for that, then rationality isn't the reason you changed your behavior.

A third explanation for your behavior (besides monkeying and being rational) is that you and others grew tired of bearing the costs of lockdown at similar times. Lockdown got significantly harder for us, psychologically, after about 4 months - it wouldn't surprise me if there's a bell curve in the population for "lockdown tolerance".

I behave similarly to Viliam, with a few exceptions. Never really frequented restaurants before, so can't say my cooking skills have improved)) but my buying-things-online skills did. I don't like spraying things with a disinfectant, but OTOH I now wash all foodstuffs that can be washed when I bring them home. My kid went to school, but only for 3 days out of 5 (it paid off, he hadn't fallen ill until the fall vacation); many parents here do something like that. Bought myself overalls for when I leave home, I had wanted to for ages and it's really comfy.

Going to the city (I live in a suburb/village) is much more exhausting now that I almost don't do it. Calling my parents is harder because "things are as usual". (I went to my dad's birthday in July.) Had problems sending in work assignments on time but autumn seems to mobilize people, including me.

Husband has had problems due to many international conferences being cancelled, the not-insignificant money for visas and tickets not refundable, networking not... working... as good without in-person communication. My department had a very hard spring getting our people back from Antarctica (luckily it wasn't my responsibility). I missed seeing a sister for the first time in years. These things all required some adjustments which by now are invisible, like regularly setting up Skype calls etc., but at that time they were a Big Deal and cost us some unnecessary worry.