Other than with a significant other, very few relationships involve being tested, pushed to the limit and challenged to within an inch of your life while wearing skimpy sweats. No, we're not talking about a fight followed by makeup sex, we mean your relationship with a personal trainer.
Think of a potential trainer as someone you'd bring home to meet Mom; your relationship with a personal trainer should be friendly, but professional, and when choosing a personal trainer avoid anyone who intimidates you or doesn't challenge you enough. Other things to avoid include getting too close with your trainer, or turning him or her into your shrink. Your trainer is there to improve your body, not be your therapist.
Personality plays a role. You will have regular "dates" with your trainer, so it helps if you get along. If you don't have a good rapport with your trainer, don't be afraid to "break up" and find someone else. You are spending your time and money, after all. Although trainers' techniques and philosophies differ, there are universal signs that indicate this one's a keeper.

• Listening to you. If you say an exercise doesn't feel right, a good trainer will hear you and determine why, give you an alternate exercise or help you adjust the exercise. There isn't one magic bullet exercise for any fitness goal and a good trainer will know many ways to work the same parts of the body.
• Understanding your goals. A trainer's job is to help you reach your goals -- not the trainer's goals -- and a first session should include an overall fitness evaluation to design a balanced, effective and realistic program.
• Teaching you. A good trainer will explain which exercises you are doing and why. This way you'll be able to continue your workouts, even without those one-on-one sessions. If you don't understand how a certain exercise will improve your fitness, you are less likely to do it.
• Critiquing you. A good trainer will watch and evaluate your form throughout workouts. Remember, critiques aren't personal. By maintaining the correct form you will get the maximum benefit and reduce your risk of injury.