Pretty sure I recently had an encounter with an FFA.
I had stopped to pick up some milk after work as one does. As I was waiting in line this lady gets in line next to me. She eyes me up and takes me all in before stepping away a few steps and saying 'I shouldn't stand right next to you, you make me feel so tiny!' And I just chuckled and said something about having that effect on the ladies at work.
She continues on with 'well you've got all that height... And all that weight..... Us Ladies love us some big men.' And went on about big men make them feel small and taken care of and such. And tried to get the cashier to agree with her about ladies loving big men.
She also made a point of reaching out to kinda pat/stroke my arm briefly and asked her little 4 ish year old boy if he was going to grow up to be a big man. He just kinda looked up up waaaay up a la friendly giant at me all wide eyed.
I really didn't know what to say through all this so I was just smiling a chuckling lightly through it all.

have you ever encountered one where you have to compress your belly into the door frame to roll your way into the bathroom?

Those are exceedingly fun after a meal /sarcasm.

Those are certainly brilliant when you can get them!

Unfortunately too many are ladder/steep stairs

I would think that it would be more of an issue of getting in and out of the pool that would stop you first

my problem is usually with bathroom doors as they tend to be smaller than your average door.

It was a pain when going apartment hunting, but found a place where the washer and dryer were in the bathroom so it had to be wide enough for them to fit through. Voila! Door I could fit through into the bathroom

There is something highly appealing about having that kind of immensity imposed on you instead of actively pushing for it. In my mind anyway.

I often imagine that if I could sign on some magic dotted line I was presented with to have it just happen to me someday regardless that I would do so in a heartbeat. So that I'd find the weight coming and coming no matter what I did or thought or said.

No such magic contracts have fluttered down from the sky however lol

Don't know if anyone else had this kind of experience, but here's what happened to me recently

I was sitting out in public just hanging out minding my own business, and this guy comes up to me saying 'hey I'm not selling anything but want to talk to you for a sec.'

Preparing myself to nod and smile as he peddles whatever religion at me, he starts on preaching about how his gastric bypass has changed his life and he hopes his story would help me just think about it.

He kept apologizing if he was offending me, but I was more offended that he said he had been even bigger than me. 'I mean, that's almost 500 lbs!' shortchanging me on my weight.

I kept debating through the conversation if I should just tell him that there's no way in hell I'd get the surgery, and that my having a fat body wasn't invitation for him to comment on it. But figured it'd be smoother just to let him say his piece and go.

I wouldn't call it painful, but I find it hard to breathe on my belly for any length of time.

And if I'm on a surface soft enough, like my bed on the memory foam, I can stay there longer, but I can't figure out what to do with my arms after a bit and I start to get cramps in my back/shoulders

How about Bed: A Novel by David Whitehouse?

I think the comment was a confusion between when a lot of people say width and mean circumference