The only way I could answer the question is "Both".
Sure, I have been walking along in a gunshow before and bought a gun that I saw laying there.
My Dan Wesson .357 was an example of that. I wasn't shopping handguns at all that day, and had never really considered owning a Dan Wesson before I picked that one up.
After I noticed it and had it in my hand, and it had passed all the quality inspection points, I was absolutely smitten by it.
I had never fired a Dan before, but had heard that they were very strong and accurate. Words like "Indestructible" and "Tack Driver" were racing around in my head and I bought it.
It was a good decision, and that pistol served me well for a number of years.
I used that pistol as a platform for my first reloading experiments and it survived my fumbling beginner mistakes admirably. It also lived up to it's reputation for accuracy.
It absolutely
Loved an Elmer Kieth load using Hercules 2400 and a 125 grain JHP. The fireball from that load was as much fun as blowing random objects up with it.
Everything about that story was spontaneous from start to finish.
My Savage .17 HMR was was different.
I started by deciding the little rimfire round was interesting. I read about it, and studied it pretty hard.
A ballistics calculator said that it could shoot anywhere from 25 yards to 125 yards and never rise or fall more than one inch from zero.
The idea of being able to shoot golfball sized targets from 25 to 125 with zero holdover really appealed to me. Just put the crosshais on it and hit it.
And the stories of tight little sub-MOA groups was something I wanted, too.
Then, Savage come out with the accutrigger. Next, they released the stainles bull barrel in a laminated thumbhole stock.
I ran around looking for one of those for several months before I actually saw one.
I like to think that this was a "Scientific" purchase. I started with the bullet, then picked a brand, then picked a model, then searched for it until I found one. The whole process took over a year.
I've been very satisfied with that one, too.
I don't think it's fair to say I buy one way or the other. My gun collection is both practical and passionate, and so are my purchases.
And who knows what I'll do next!