Can become lonely and go through tough times, because of that.
Despite generally having a good sense of self, can tend to be self opinionated and put pressure on yourself to succeed; no sibling to lean on for advice.
More likely to be spoilt, theoretically, as they are the only child.
Only Child (Final Thoughts)
Ironically, it may be that they are more disciplined; they are taught to tackle life by sticking to specific guidelines.
Know how to pass the time; more likely to find hobbies like sport, art and music.
They realise that there is nothing wrong with being independent and/or introverted.
May have strong opinions!
If someone doesn’t have siblings, they are possibly more likely to realise you only need to be happy within yourself, first and foremost.