Do you know of anyone who would want someone with an unhappy attitude trying to teach others about God? I don't think anyone would, that I'm sure of. The sight of an unhappy person wanting to teach others about the Lord is a picture that would not be welcome anywhere.
Positive attitudes can impact others. The children of Israel were belligerent and hopeless, but Moses assured them that God would rescue them. Moses had a positive attitude! When it seemed as if they were trapped, Moses called upon God to intercede. Instead of giving in to despair, we should borrow Moses' attitude to "stand firm" and see the deliverance that the Lord will achieve.
A circumstance occurs in which our life is altered. This could be a catastrophe within our family or friends or a loss of a job or the loss of good health. Our perspective at any event that we encounter either helps us or hinders us. If an unpleasant incident occurs, we need to stop and consider our blessings. Positive attitudes will help overcome adversity. What is your approach when the task you have been given is not up to your true capability? The task at hand may be all you can do, or it may be the work God wants you to do.
"The sentence which has most influenced my life is, 'Some persons grumble because God placed thorns among roses. Why not thank God because He placed roses among thorns?' I first read it when but a mere lad. Since that day it has occupied a front room in my life and has given it an optimistic trend." (Benjamin Franklin)
There is little difference in people... the little difference is attitude. The big difference is whether it is positive or negative.