Loving this thread!
I've flown first class on two occasions soon to be a third & fourth time - we travel quite a bit so build a lot of Avios and air miles, a lot of saving and I also work in travel.
but usually, For long haul we always try to travel business class and as much as it is more expensive, for someone like me who struggles on planes its definitely worth every penny.
My first time flying first class was with Qatar. it was just after covid so my partner and I had the whole first class cabin to ourselves on the way there. I remember I'd never seen a bathroom on a plane like it - I went in needing the toilet and couldn't find it! I'd had a few fair champagnes by this point and took a while to realize it was underneath this massive seat

We also got escorted down the plane to the bar which for me was just out of this world, being sat in a private bar with a drink and just looking out the plane window. We flew to Doha and then on to Thailand.
and then the same route home.
I'm not a wine drinker, preferring spirits or beer so we had been drinking some cans of beer in the lounge in Doha on the way home and there was this older very posh couple, well imagine the looks the man gave me when he got on the plane to see me sat in first class with my can of stella!
We weren't sure if we would get the chance to fly first again however we did this year going to LA with BA and we got to use the Concorde room which has been a dream of my partners for years. So relaxing in there, really didn't think I was in an airport not to mention the cocktails - I'm lucky to remember getting on the plane. The flight itself was so comfortable, and the staff so friendly - anytime I went to the toilet I would come back to one of their summer cocktails waiting for me. The little amenity kit I got from Elemis was packed with stuff - i still use the bag as a makeup bag.
We are going to Thailand in January and America in April for our honeymoon and flying first class on both occasions - we got a great deal for Thailand with Swiss Airlines and for our honeymoon, we booked business class BA and upgraded with our Avios points to first.
Flying first is something we never take for granted and we know how lucky we are on occasions to do so.
My first time flying business was around 5/6 years ago, with BA to Thailand and I knew then I'd have to do this with every long haul flight -the room to actually get comfortable and lie down to sleep, the privacy, and the food/drink menus. I struggle with a 3 hr flight to Spain so this was a dream to me and we've saved and worked hard to be able to do that every year since we have gone back. It does make all the difference for me when I get to the other end.
I would say Singapore Airlines has one of the best business class we've been on, we got lie flat beds on one of our flights home and the screens are huge so I was in my element watching re-runs of Grey's Anatomy! They gave you little teddy bears too which was a nice souvenir
I usually find the airport experience a lot nicer too, I'm a very anxious person so going through security and being in lounges etc I find just a lot less overwhelming.