I have been on two 10-day Vipassana meditation retreats. One took place in Texas and the other in France. The first one was much more valuable for me. It was SE of Dallas iirc next to a ranch where there were some cows so it was a really serene place. I had been meditating beforehand for a year or so which definitely helped prepare me. There were some people who went into it with no prior preparation, which I thought was pretty crazy but I think just about everyone finished the 10 days, minus maybe 1 or 2 (at least on the guy's side). I don't remember how many there were in total but I'd say about 100.

I had some pretty crazy revelations. For one thing, I had never really sensed my body up until that point. In Vipassana you literally try to feel the physical sensation of every square inch of the body. I remember during one of the group meetings someone was talking about feeling their gums. It hadn't even dawned on me that I could focus on my gums and feel them. It's a pretty wild experience to just sit and focus on physical sensation for 10 days straight. Even when you're not in the meditation hall, you're still focusing on some kind of physical sensation.

Another interesting revelation I had came when I got sick from eating some of the food. They cooked really amazing Indian food, but my body just wasn't used to it and I got the shits for a few days. It was a really weird experience not being able to tell anyone that I felt sick (of course if it got bad then I would tell the supervisor assigned to my group). I had pretty bad diarrhea for 2 or so days. I had never thought how much I depended on being able to complain to others about feeling discomfort to give me a sense of well-being. It was interesting how my mind started to consider all these negative scenarios if something bad happened and no one knew I was feeling ill so they didn't come to check on me. It was kind of funny going through my head wondering if I should tell the supervisor that I was shitting myself just for future reference in case I shat myself to death. I decided I was over-reacting and just kind of observed my mind freak out about it.

I remember having the sensation of having a big revelation although not entirely sure of the content. I kind of just assume that it's integrated itself into my mind. It may have had something to do with the idea that what my mind perceived as reality didn't necessarily have any truth to it. Particularly when it comes to how I perceive others' perceptions of me. For example, I could have a sense of how a friend, family member or even some random person thinks of me that might be totally off base from what they themselves actually think about me. An interesting book that touches upon this topic is "One, No One and One Hundred Thousand" by Luigi Pirandello.

Aside from that, it's mostly given me the ability to just take a break from feeling stress/anxiety/anguish, focus on the physical sensation that is associated with it and take some comfort in knowing that it's not permanent. There's the whole idea that when something negative occurs in our lives, we prolong its existence by trying to push it away when instead we should observe it, let it pass and maybe even learn from it. As someone who was diagnosed w/Hashimoto's I've had periods of my life where I feel really shitty and at one point I dipped into a really dangerous depression (prior to the retreat, part of what motivated me to do it). I should note that I mistakenly had the impression that meditation would simply let me "zen" myself out of these modes. Unfortunately, they seem to carry some inertia with them and so meditation was not the superpower I thought it might be to attain a state of happiness and well-being at any instant I desired, however I certainly take value in my ability to not amplify them anymore and to be able to look at them objectively and take the necessary steps to dig myself out of those holes.

I've also done several Ayahuasca retreats, some of which I really valued for their emphasis on connection with the people doing them with me. Silent meditations are great, but they certainly don't fulfill any need for social interaction as you pretty much have to pretend that the others don't exist and can't talk to them. I did think it was funny not to hold the door for people behind me going into the meditation or dining hall with the justification that as far as I was concerned, they weren't there.

I also did funny things during the retreat like saving worms from getting stepped on when they tried to cross the sidewalks or staring at ant hills. It's a crazy experience being with your own mind for 10 days, I'd recommend it to everyone. Not easy, but entirely doable and will almost certainly change your perspective on life. I scheduled mine through dhamma.org, it's totally free (free housing, free food) and they accept donations at the end if you'd like. I do think the program needs to be updated a bit to integrate better with today's society, but of course that's easier said than done.