I think frustrations depend on so many variables, like where you are at in life. Are you working? Retired? Kids? No kids? Single? Married? It's different for everyone.
We started full-timing as working-age RVers with no kids and a dog, on sabbatical back in 2007. We haven't stopped although this is the first winter we are not spending in an RV (because we are up in Alaska for the season). Being out of the RV for the next 10 months (yes, we are going back to life on the road after our AK adventure), I'm able to more easily reflect on what we loved / don't love about full-timing.
Top 3 Full-time RVing Frustrations for Us as Working Age RVers:
1. Lousy, Expensive, Complicated Health Care Coverage. Getting coverage out of state is difficult and expensive. We are currently Coloradoans but formerly Texans for 9 years. We finally have health care across the west coast because we were able to get Kaiser Health Insurance as Colorado residents, and Kaiser is in most West Coast states. But it's not covering us here in Alaska so everything is out of network.
2. Internet Coverage is Expensive. It's expensive to maintain reliable, redundant internet coverage no matter what providers you use. We average anywhere from a low of $200 to $350 a month depending on the plans we are using.
3. Finding Long-Term (30-day) RV Campsites is Tougher. RVing is more popular than ever, and finding a good site in a good, affordable park (say nightly rent less of than $80) in more populated places like the West Coast is tougher these days.
Otherwise, the usual frustrations that life will throw at any couple who lives and works together in a small space are pretty typical of most sticks and bricks folks. And although I wouldn't call it frustrating, I do miss building long-term connections in a community where people know you, and vice versa. The only thing that's come close to that for us is staying seasonally at our favorite park in the SoCal desert every winter. This is the first time we won't be there in 7 years, so we'll see what this community is like as far as getting to know folks. So far, so good. But I'm looking forward to the day when we don't have to worry about the usual domestic/renter responsibilities like trash service, snow removal, etc.