If it’s flying we’re talking about, meaning flying the plane in relation to the air and terrain, I could do it several times a week and enjoy it. The rest of it, paperwork and procedural hassles, I simply dislike, without exception. If my flying involved a lot of stuff like flight plans, calling airports on the phone, slots, journey logs, aircraft log entries for every flight and so on, one flight would be too much (I would pursue other interests)
I’ve been flying for good portion of my life. Starting as young as 16 flying gliders, and now being over 50, you can guess I hardly can get fed up with flying. I’ve never been professionally involved in aviation except short period few years ago when I was co-owner of startup ATO.
Coming back from longer trip at 16000ft over pretty terrain, it again struck me how fortunate we are and how wonderful aviation is. And when I got into the LA basin and got an arrival procedure to follow, with lots of traffic and amendments, it was so much fun (mind you, it’s not always fun and it’s easy to get overwhelmed and not have any fun at all, but on this day the challenges were within my capacity). And ultimately that’s what makes aviation so rewarding – it’s challenging. You tend to give up on things that are not.
The more I fly, the more I want to fly. In the summer, especially the part when I ferry my kids around Europe to see their grandparents, I can do 3 to 5 hours a day a few days in a row. The first thing I do when I have time after landing is plan the next flight.
Cars are much quieter however. Even a Trabant is orders of magnitude quieter than an SEP. It might even vibrate less 
Flying is quite exhausting to me, mainly because I lack currency I think. If I was as current as I am as a car driver I could probably fly for hours every day. As it stands the most that I’ve flown on a single day was two 100 nm flights, each taking slightly under 90 minutes. I don’t think I would want to fly more than 2×2 hrs on more than twice a week at the moment.
I don’t think I would get tired of it. The more I fly, the shorter the idle time in between gets before I “have” to fly again. I find instructing much more varied and rewarding than I thought it would be up front (for several reasons). The briefing also takes time, so the actual flying time gets nicely portioned out in a day or evening with interesting time in between. Towing gliders can be exhaustive. It takes about 1 hour to get to the glider site in a Cub in the morning, then 20+ tows all day, and 1 h in the Cub back again late i the evening. After such a day, I don’t “need” to fly for several days, mainly because of fatigue (if I was 20, I guess I wouldn’t mind doing it 7 days a week at least for a while). It’s been some time since I towed now, and feel the “itch”.
Cross country: I try every once in a while, but I just don’t “get it”. More than 1 – 1 1/2 hour straight and level, and I start to wish I already was there and back again, or took a car or an airline. Flying to fly-ins etc is fun though. On the other hand, I have started liking old school cross country. Paper map, clock and compass. I would rather use SD for “daily use” because it is so quick and simple (and therefore also safe), but old school nav is actually fun in it’s own right, particularly when the weather is less than optimal with low cloud layers and the watch becomes important (there is always a moving map somewhere, so I won’t get lost or anything).
Then there is Nov-Feb, dark and cold, better used for building/maintenance, and gives a long enough brake.
I think what happens is people find ways of flying they like, and don’t get tired of, or they quit.
I love to fly – period. That said, I much prefer going places than bimbling about the local area. I do the latter mainly to stay current, although a night flight over L.A. is one of the more spectacular things one can do in GA flying. I also find it concentrates my mind on something that’s totally outside my day-to-day life – walking out to the airplane the worries and stresses of daily life fall away. In a way, flying is the most relaxing thing I can think of. Therefore – I doubt I ever tire of it!
I get Ultranomad wrote:
I don’t get tired of flying as such and would gladly do it every day, given the opportunity. The strongest limiting factor is stress from all other aspects of life: if it’s not too high, flying actually cures it, but if it’s excessive, it becomes unsafe to fly in the first place, and this is what actually caused my IR to lapse.
Flying for the just fun of flying, I go into something cheap per hour that does not have shiny avionics, no flight planning or anything just jump and fly it locally (e.g. vintage twailwheel aircraft or wooden gliders) and I never get enough of it and it melts all the stress from the week
Flying for going A=>B, I go into something cheap per nm with shiny instruments and do proper planing and enjoy it, though it puts you under a bit of stress as you tend to think more, so there is point where too much flying here hurts a bit
I never understood how some enjoy flying locally long hours in complex/fast aircraft, personally it just kills me and besides it breaks my bank account 
Instructing is a different matter
I love the flying. I also like the flexibility and the opportunities it gives but the flying itself most of all. It is a technical challenge and a great break from everyday life.
