If Pip had not received his "great expectations" and never left Joe's forge, how would his life have been different?That is are the lessons he...

A central concept you need to understand to answer this question is class consciousness, or how Pip becomes aware and dissatisfied with his humble origins. We can see that this comes through his first meeting with Miss Havisham and Estella, and how he becomes ashamed of his humble roots. The end of Chapter 9 clearly marks this event as a fundamental point of change in his life.

That was a memorable day to me, for it made great changes in me. But it is the same with any life. Imagine one selected day struck out of it, and think how different its course would hgave been. Pause you who read this, and think for a moment of the long chain of iron or gold, of thorns or flowers, that would never have bound you, but for the formation of the first link on one memorable day.

This passage is key because it introduced the notion of being "bound" - something that is developed in Ch. 13 when Pip is "bound" into his apprenticeship. This indicates how Pip sees his lowly position. It is important to note that this awareness or realisation comes before Pip receives his "Great Expectations", and so it is likely that if Pip had not received his Great Expectations he would have lived a frustrating and sad life, consciously aware of the limitations of his position in society and unable to do anything about it. With his visit to Estella, gone is the ability to accept his fate.

Your second question seems to tap into a big issue with the book - is it better to remain ignorant and happy or wise but have to suffer? Certainly the wisdom that the narrator demonstrates has only come through the sufferings and trials that the younger Pip experiences - there is a definite sense that this is a novel of maturing, of change and growth in character. The incident where Pip saves Miss Havisham from being burnt and also burns himself in the process, and his loss of his "expectations" and the fever that cripples him have a sense of purgatorial repayment for the wrongs that Pip has committed - he learns just how much of a snob he has been, and how he has hurt others through his actions, and begins to right his wrongs. Thus we see at the end of the novel a sadder, but much wiser Pip, who has definitely learnt a lot through his experiences and regrets his past mistakes and errors.