Honestly, I'm rarely disappointed. My love for firearms is deep, and I love each for what it is. I love the light weight and durability of Glocks, the tradition and satisfying thump of the 1911, the smooth lines of a Beretta, the businesslike profile of an XD, the slender grace of a CZ-75 or BHP, the blast of an 870 or a 590 alike , the fun of any .22, the blistering awesome of a full auto FN P90, and the sweet, smooth controllability of a full auto HK MP5.
In the end, I think I'm barely ever disappointed because I don't expect any gun to be what I need, I just expect it to be what it is and then match the favorites to my collection.