The first handgun I ever bought started out as a disappointment. I bought a Glock 23, having never fired anything other than some air-rifles and a .410 shotgun before in my life. The checkering on the grip was painful, the recoil distressingly snappy, and the gun would produce patterns, instead of groups.
That was all me, though. I eventually filled the checkering with black silicone, and learned how to shoot properly (putting more rounds through it than have gone through many of my other guns put together.) Now, it's not the most accurate autoloader I own, but it'll produce nice groups at 25 yards all day, and has been treated to night-sights and a nice carry rig.
Now the only two handguns that I could say were real disappointments was an old Browning Baby .25 ACP, and a Taurus .357 Magnum. The Browning would keep all six bullets in an area the size of a door at seven to ten yards, and had a reliability best-described as 'indifferent.' The Taurus looked nice, but was quirky. Fortunately, I never actually owned the Browning (I only had it because I was asked to clean it up and fix it,) and the Taurus was traded in for a Marlin rifle for zero regret.