Recently, after I spoke about my personality framework, the Four Tendencies, a woman came up to me and said, “Because of your talk, I’m going to do something different.”

“What?” I asked, curious.

“My daughter plans to take the GRE. She keeps telling me, ‘Mom, I need to take a class.’ And I kept saying, ‘No, if you’re motivated to take the test, you should be able to buy a book and study from that.'”

When I heard that, I wanted to jump up and down and say, “No, no, NO! You’re making the classic mistake! You’re saying the dreaded ‘You should be able to…!’“

Fortunately, she continued, “After hearing your talk, I realize that she’s right. If she needs to take a class, she should take a class. She’s an Obliger, and she needs the accountability of a class.“

I was very relieved to hear that. I’ve found that one reliable sign that we’re about to make a big mistake, when we’re trying to help someone else (or ourselves) to change a habit, is to say “You should be able to.”

• “If you want to exercise more, you should be able to get up an hour early and go to the gym before work.”
• “If you want to eat more healthfully, you should be able to indulge in just half a dish of ice cream each night.”
• “If you want to stop spending so much time on your phone, you should be able to limit Candy Crush to just twenty minutes a day.”
• “If you want to get that report written, you should start early and work on it a little each day.”

When we say “You should be able to,” we’re talking about a fantasy person, one who may bear no relationship to the actual person we’re talking to.  And usually we’re talking about what habits would work well for us.

• That advice about exercise works for a morning person, but not a night person.
• That advice about eating works for a Moderator, but not an Abstainer. Ditto, that advice about technology.
• That advice about working works for a Marathoner, but not a Sprinter.

If there’s one thing I’ve learned about habits, is that each of us must change our habits in the way that’s right for us. There is no “should be able to” — it’s just a matter of what works.

“Should be able to” is harmful, too, because it makes people feel bad about themselves — “I should be able to get up early and exercise; I must be lazy” “I should be able to eat half a dish of ice-cream; I must lack self- control.” No! This habit is just being set up in the wrong way.

If someone keeps telling that you “should be able to” do something, but it’s not working for you, try something else! Night people shouldn’t try to do things early in the morning. Abstainers find it easier to have none than to have some. Sprinters find it easier to work for a shorter, intense period than to work over a long period. There are many ways to build better habits and the lives we want.

There’s no right way or wrong way — just what’s right for you.