What does Mr.Lamb mean by "everything's the same,but everything's different"?

Mr. Lamb's perception of life forces Derry to be optimistic about life as well. This change in perception makes Derry view his "same old life" in a different manner. Optimism can make the things that seem staid to us appear different. If you can view life as having to offer us a number of things, we can find new meaning in the "same-old life". This was the notion that Mr. Lamb was trying to teach Derry. He wanted to inspire Derry , so that he would begin living his life again. Being a youth, Derry should not be restricting himself, but going out and enjoying life. Seclusion would only cause Derry more harm. Hence, Mr. Lamb wanted Derry to change his concept of life, so that he starts to perceive life in a new manner.