1. You don't sprint back on defense.
Instead of sprinting back on defense and helping your teammates stop an attacking offense you just run (or jog) alongside your opponent, satisfied that you are not the last one down the floor. Of course, if your teammates do manage to get a stop without your help or if the offense turns the ball over then you are available to suddenly turn around and race to your own basket to get a lay-up.
2. You let your opponent box you out.
As soon as the shot goes up you just stand and watch. Even worse you become a "hummingbird," the type of player who runs right into the back of a defender trying to box out and then you bounce up and down on your toes and flap your arms but you never really go anywhere. You don't fake, jab, spin, swim or make any other attempt to get inside position or get to the ball. Rebounding, especially on the offensive end, is largely effort and desire and so if you won't rebound you're not playing hard.
3. You don't dive on loose balls.
I can take one look at your knees and get a pretty good idea of how hard you play. Are they covered in floor burns or are they as smooth as a baby's bottom? Some see a loose ball and treat it like it's radioactive by heading in the opposite direction as quickly as possible. Others just stand there and watch it roll or even try to make it look like they were going after the ball. That way they can tell their coach or teammate, "I was going to dive on it but I thought Taylor was getting it!"
4. You won't take a charge.
Glen "Big Baby" Davis you're not! Taking a charge could hurt and you don't want any part of it so you've found ways to avoid the contact. Maybe you just rotate over a second late so you don't have time to get your feet set or maybe you don't rotate over at all. If you do find yourself in a position to take a charge, you take on the roll of "matador" and open up the entire lane for a straight drive to the basket.
5. You won't sprint to fill the lanes on a fast break.
You might not get the ball so why run that hard to fill a lane, especially if you are one of the first options in your set offense? Paul Westhead, known by many as the "Guru of Go," has stated that more offenses sabotage their own fast break opportunities by not running hard than do defenses by getting back
6. You could beat your opponent to a spot and you don't.
The game of basketball is largely about real estate and geography - whoever gets to the prime spots first has a huge and distinct advantage! Whether it's playing weak side defense, chesting up cutters, or flashing hard and strong into the low post, whoever gets top the spot first usually wins. Letting your opponent constantly beat you to all the important spots is a sure sign of not playing hard.
7. You get upset and/or defensive when an opponent (or teammate) plays harder than you do.
This is by far the worst as far as I am concerned. Someone beats you down the floor, takes a charge when you drive, bumps you when you break across the key, dives on a loose ball while you stand there and what do you do? You get mad! Not disappointed at your own lack of effort but mad at your opponent (or teammate if you happen to be in practice) for playing harder than you play. If you are the type of player who doesn't play hard at least own up to it and show some respect for the player who plays the game the right way!