I have been pulling single shots for practice; to me they seem more finicky than doubles and thus a good way to develop skill. One problem I was having had to do with the mirror-like smoothness of the stainless steel basket; the smallest disturbance (a slip of the tamper, bumping the portafilter) would quickly damage the puck. Not being the kind of fellow afraid of ruining an inexpensive, easily replaceable part, I slightly sanded and then buffed with steel wool the inside, which now has the appearance of brushed steel.

The end result was quite good. It significantly improved the ability of the puck to stay in place. Before the slightest mistake would loosen the puck. Now I have to really screw something up for it to do that

I just wanted to share this in case somebody wanted to try it.

I seem to recall a discussion on CG of sandblasting the inside walls of a basket (after protecting the bottom). I don't recall the results.