I don't actually use my chair for sitting so much. I use it more as just my "legs;" to get from A to B, so to speak.
I usually sit on the couch to watch TV, sit in the recliners of on couches at friends' houses, and do the same at my parent's house when I visit. Half the time, someone else ends up sitting in my wheelchair until I need it. When I'm out at the lake with a couple of my friends, we usually park in the shade, and I sit on the tailgate of the pickup (just carry an extra cushion...metal on the arse can cause some issues), or in the seat on the boat (belted in of course). I have unfortunately had to use the wheelchair for about the last 2 weeks while at my computer due to my old office chair falling apart with me in it (not fun). I also get up onto barstools (you should see the stares and reactions...priceless!), into booths, into movie theater seats, etc.
Most importantly, remember that you are not your chair. It is just your replacement "legs." You only have to use it to get from A to B. If you want to sit on the couch or recliner, go for it. There's no reason not to. If you want to stay in the wheelchair, that's your call too. To hell with what the rest of the world thinks. Do what you want to do, not what you think others are comfortable with. If someone is bothered by you sitting somewhere other than a wheelchair, that's their problem. It's
not your only seating option, especially not in your own home.
It was hard for me to get used to my legs not working as well. I've gotten out of the pickup without getting the chair out before...Landed face and shoulder first. That was embarrassing.

The second time was worse, as it was on concrete. Luckily, I didn't hit my head that time.