It is interesting the optics of optimism talking about pessimism, is that the circumstances around us at any stage of our life or those around us in most of the time defines our personality and way of acting, but it depends on ourselves to stop and think, what we really want and want to project to others and if that joins a positive stimulus, ie a hope situations will be more manageable and different.
And with respect to failure, it is not that we want to fail but when it happens, we must take them as benches to overcome adversities and not as holes to sink into discouragement.