On a recent visit to a former client's workplace, I noticed a poster entitled, "I'm Not Changing!" Change at any level, be it personal or professional, is always difficult. It's the subject of countless books and articles, including my own.

I've been in the business of change for well over twenty years. Every year I seem to collect yet another reason, however nuanced, for why we, as well as our businesses, have such a tough time changing.

Here are twenty reasons -- all different flavors of resistance and pushback -- you and/or your won't change.

1. Fear. We have an innate fear of the unknown. "I'm afraid of what will happen."

2. Myopia. We can't see that change is in our broader self-interest. "This won't help us."

3. Selfishness. Unless change immediately pays off for us, we'll resist it. "What's in it for me?"

4. Homeostasis. Equilibrium is more comfortable, change is uncomfortable. "I'll feel better when things are normal."

5. Ego. Those with power have to admit they've been wrong. "I feel I've positioned us well for the future."

6. Sleepwalking. Too many people live unexamined lives. "I just don't get it."

7. Lack of confidence. Change threatens our self-worth. "This will reveal the true me."

8. Timing. Certain preconditions have to be met for change to occur. "I'll change when the time is right."

9. Human nature. We are naturally self-centered and change requires some selflessness. "Others will benefit more than me."

10. Inertia. A body in motion takes considerable force to alter course. "We're already down another path."

11. Short-term thinking. People have difficulty seeing and supporting long term visions. "I can't see that happening."

12. Perversity. People perceive only the opposite or downside outcomes of the change goal. "That'll make things worse."

13. Complacency. We like the path of least resistance; we're not natural maximizers or optimizers. "I'm satisfied with the ways things are."

14. No constituency. The power base of the status quo is greater than that of those trying to bring about change. "There's no critical mass behind us."

15. Groupthink. Social conformity limits our thinking. "What does the group want to do?"

16. Short selling. Perceived lack of knowledge, skills, tools and experience. "We've never done this; we don't know how to do this."

17. Exceptionalism. People can't see the situation objectively. "That may work elsewhere, but we're different."

18. Futility. Change is seen as superficial, not worth the effort. "Why go through so much pain for so little gain?"

19. Cynicism. People distrust the intentions, motivations or track record of change. "Here we go again."

20. Future shock. Grand scale change makes people hunker down, sensing they may not be able to adapt. "I smell disaster."

Does your company fall prey to any or all of these in some respect? As the new year approaches and you begin to think about new goals and directions for yourself and your company, you might want to keep an eye out for when (because they will!) resistance and pushback disguised as one or more of these twenty reasons creep onto your change radar screen.