Tactical repeats

It's funny how certain combinations can show up again and again in games. Sometimes, I remember having the feeling that using such combinations was cheating - I didn't really win that game, I just used that old trick again. I wonder if there is something to that sense though. We can begin to rely on specific tactics in certain kinds of positions. If you've got a trick that the opponent seems to fall for over and over again, you can get lazy and fail to develop a greater sense of the nuances of the position(s).So here's a good case in point. I was black here, and this is just the sort of position where I developed a pattern in 2007 of always striving to nab the a-pawn.
14...Nc4
15.Bc1 Nxa3
16.e5 dxe5
17.Bxb7 Qxb7
18.bxa3 exd4
19.Rxd4 and I went on to win after a long struggle.

Here's another example, same theme.

Once again, 16...Nxa3 works to perfection.

And another one:

And of course, Nxa3!
It gets to the point where you can think of it, Sicilian defense 101 - go for the a-pawn with your knight and hope your opponent has an undefended knight on c3...

I think though, that the more important lesson to draw is a certain tactical awareness so that you can be primed and aware when similar opportunities arise in disimilar positions. For example:

Here I was white against a strong expert, and it was with great relish that I unleashed Bxh6! which let me off the hook after a long a difficult effort to mobilize my hanging pawns, and I went on to win.