as fred said this is much more than personal prefrence, go buy a tub of flux paste.
90% of you are not soldering correctly in the first place, its common. allthough you get the job done and it looks good and works, your skills are flawed. I am sure 90% of you guys apply solder to the tip of your iron and then apply that to the work piece. although this works, it is not technically correct. when you melt the solder to the tip of your iron, the rosin/flux melts and disipates at a lower temp then the solder does, therfore in the seconds it takes to move the tip of your iron to the work piece, the flux has burned away. that is where the small bit of smoke comes from when melting the solder (pure solder wont smoke) you are supposed to apply solder to the work piece at the same time you are applying the heat. this takes two hands and leaves nothing to hold the work piece.