Second, at times it should be your obligation to be a jerk to others. Not saying always, but where not doing so puts you into a worse place than you would otherwise be, you should.

To explain (followed by an extreme example): consider the most important things you need to accomplish in life (remember also that these will vary depending on what you intend to achieve with your life) -

1. Stay alive. You can't do squat if you're dead.

2. Love unconditionally, but take no crap.

3. And so on.

If being an arse to someone keeps you alive then this may give you the opportunity to save your child's life. There are many less-extreme scenarios that are just as valid. Why, for example, does the FAA suggest putting your own oxygen mask on before helping others?

PS. Everybody can be successful. Ref. Wallace D. Wattles' vol 1: The Science of Getting Rich