If the trip does not test your mettle, then I'd say it was probably not an adventure
The comment above, whether intentional or not, implies that a trip has to have some level of adversity to be overcome in order to be considered an "adventure". For me an adventure is when I go on a trip (3 hours or 3 months) where I experience a sense of exploration, perhaps deal with unexpected setbacks, but come out the other end on balance having enjoyed my trip while learning something new and feeling better for it.
I suspect that if someone were planning to go on a trip knowing beforehand that they were going to encounter foul weather, mechanical issues, perhaps a crash or two they would not move forward just so they could say they had an adventure. Then again, they might move forward knowing those possibilities exist if they felt the end result would be to see, visit or ride something new and unique that made all the adversities worth it, but I think that would be a personal decision.
I have spent a lot of my riding in the mountains, where I have often encountered cold, fog, snow, occasional ice (where it is difficult to keep the bike from sliding out from under you), all-day rain and sometimes roads torn up in unexpected places due to construction, flood washouts, etc. At the end of the day, on balance, I still find a way to enjoy the ride (low overhanging clouds on mountain tops during rainy days can still be quite beautiful).
Based on my experience I expect that I will have to deal with the types of challenges mentioned above, they are par for the course. If they happen on a route that I have ridden before then it was simply a good ride for me. On the other hand, there are riders who come with me that deal with these challenges for the first time and it is an adventure for them. Same for me - if they happen on a route where I am exploring and find some unique new road, a glorious new pass, or a great new hotel/restaurant to enjoy, then the trip was an adventure. It's all personal.