It is nice when you are sure of yourself, a privilege reserved for the young and ignorant. As you get older, and are afforded the time to reflect, you realize there is no such thing. Or at least there shouldn't be.
Unfortunately this realization sometimes comes at times when the inherent weakness associated with self-doubt is not very welcome.
Often, self worth is measured by arbitrarily quantifiable parameters, like the amount of stuff you own, or the number of friends you have. As much as the prior is clearly a fallacy, simply measuring your ability of hopefully disposable income being indirectly reciprocal to your understanding of the meaning of life, the latter is a more inescapable expression of ones social abilities. How many friends does it take to make one feel better than Jefrey Dahmer? And how do they taste?
What is the meaning of feeling alone? Is the lack of companionship an indication of being a misfit, or an outcast? Or a simple indication of poor hygiene or halitosis? Is feeling not to fit in a badge of honor, or an indication of something more sinister, like being a certifiable asshole hiding behind an air of unapproachability? Or not having a football team, or no stripclub stories? Maybe I have to swear more.
How long does it take living as a stranger in a foreign country to feel you fit in? When is it no longer appropriate to use that as an excuse and face the fact that it's not them but you?
At what point is one not giving a fuck the consequence of not giving a fuck?