What other people think of us.

What we think of ourselves is very important. What other people think of us is not important. We tend to be concerned with what other people think of us, but what someone else thinks of us really has no bearing on our life. What we think of ourselves is EVERYTHING.

If we work at being nice people and work towards accomplishing something, others will probably like us. But if we go around concerned about what other people think, we're not likely to accomplish very much.