Recruiting with no balance in mind. Recently I've had a team with a great, deep backcourt but no real bigs to help them. Also recently had a team with a great frontcourt, but a shallow, so-so backcourt that couldn't get them the ball or keep defenses honest by providing an outside scoring threat. I've also taken the odd guy that doesn't fit anywhere, usually because I fall in love with his athleticism. So now I've got a SF with a 95ATH and 85DEF, but a 20 in speed, 30s in per/lp/bh,pas, and 15 rebounding. But dang he looks good during warm-ups.
And like rednu mentioned previously, have had teams that couldn't pass and it's horrible.