Computers, of course, can play at very high level these days. They aren't strategic geniuses yet, but they have impeccable tactical sense. The hardest problem is to come up with realistic weak opposition for lower-level human players to brush up against. So, I recently purchased the latest Chessmaster software. It's not the strongest computer program available (though it certainly is grandmaster-strength) or the best in terms of, well, various other metrics chess players use. What differentiates it is that it's pretty much the most user-friendly, especially for beginners. I bought it because it was on sale and it's supposed to be fairly good at what I really needed: providing a bunch of opponents of various strengths to play against.
So, to get back in shape a little bit, I set up to play a tournament of G/60s against a bunch of weak opponents, just to get used to playing at longer time controls before using so much of my day against strong opponents. But, come on, a 1500-rated opponent hung a piece on the fourth move. Now, 1500-rated players occasionally drop pieces, even when they're playing at a long time control. But not on the fourth friggin' move. The opponent gave up a piece for a pawn later, as well. Up two pieces for free. I mean, I know 1500 is weak, but it's not "hang a piece on the fourth move" weak. But that's what it's like.