I've gotten various firearms for various reasons.
It started out after my dad passed away. My mom was very anti-gun, so she gave away all of his guns. He wasn't a collector, or even had amazing pieces, but they were well cared-for.
So my first buy was, well, what's the most versatile gun out there? Considering the wide assortment of amazing stuff you can put in a shotgun, that's what I looked for. And the most versatile shotgun, which at the time looked to me like the Mossberg 590. I recall wondering at the time why nobody made a magazine-fed shotgun. You can get them now, oh well. But at least with the Mossberg I can load up with 8 in the tube and 1 up the spout.
I also needed a .22 rifle. I asked around, and everyone said, the Ruger 10/22, so I got one of them and wound up customizing it heavily.
But I didn't have a sidearm. First, I got a Ruger MkII because I figured, if I can't shoot basically a target weapon, I had no reason or excuse for something else. I shot the heck out of that Ruger and decided it was time to graduate.
So I got a Ruger P95DC because the action was so similar to the Beretta M9 and it all made sense to me to do things that way.
Since I was stocking 9mm, I figured, maybe a better varmint rifle would be a 9mm, so I got a Marlin Camp 9 -- which might be the most accurate weapon I have. It has destroyed rabid skunks and racoons whenever that was needed.
Meanwhile, the Ruger P95DC proved just too heavy to carry all the time, when I decided I wanted to carry. First off, it had to be light, or I wouldn't want to carry it. Second, it had to hold lots of rounds, Third, it had to fit my hand -- they're a bit on the large side, and I don't want to shoot a pistol with two or three fingers. Fourth, as much sight radius I could get away with. Sixth, it needed to be an inherently accurate weapon. That brought me to my Browning 1911/22.
And that's my whole collection, outside of my BB gun (nearly 60 years old) and my .177 air rifle, that I got back in 1972.
Long story short, I never went shopping for weapons before first having an idea of what I wanted.
Edit: I failed to mention my DPMS LR-308. I went shopping for this Civilian Battle Rifle (CBR) when the hysteria over 'assault rifles' reached its peak, and even my state of Iowa seemed like it might be overrun with the frenzy of "ban the black rifles". So, after lots of research, and talking to people, I got the DPMS. I've never regretted the least penny I spent for that rifle.
The DPMS is dead accurate, so is my Marlin 9. But you need the right tool for the right job. And I'm confident that they both shoot better than I do, which is exactly the way the world should be.