Calm and Violent Passions

Hume makes a distinction between calm and violent passions. He says “Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them.”
Hume is saying that passion and reason combat each other and conflict. He is saying that reason alone can never, alone, motivate a person to do a certain action. He says this because he believes that reason can never oppose passion in a direction of will, and that passions are never unreasonable. And, since reason exerts itself without producing any sensible emotion, reason should not solely used to make a decision.
He means that reason is not intact with reality. He thinks that it is too removed.

Contemporary examples of this can be seen. For example, reason can be viewed as today’s “book smarts” while passions or emotions can be viewed as today’s “street smarts”. Without the street smarts, the book smarts is useless. You would not be able to interact with society, which in turn would not allow the book smarts to be of any good. Also, a passion could be seen as a positive obsession. When Hume says violent passion, a negative connotation is attached, which can be rather confusing. I would use an Olympic athlete as an example of a person with a violent passion to explain that it is not a negative emotion.

Interesting:
Nothing is more usual in philosophy, and even in common life, than to talk of the combat of passion and reason, to give the preference to reason, and assert that men are only so far virtuous as they conform themselves to its dictates. P.265
I think that this is obvious, and I understood that reason does not match up with our passion. This is a discussion that needs attention.

‘Tis obvious, that when we have the prospect of pain or pleasure from any object, we feel a consequent emotion of aversion or propensity, and are carried to avoid or embrace what will give us this uneasiness or satisfaction. P.266
People will avoid situations in order to escape pain. This can be seen in how people interact with each other. When presented with a challenging situation, even though the end means might be rewarding, people will bypass the challenge because they do not want to exert the energy and feel pain.

But nothing has a greater effect both to increase and diminish our passions, to convert pleasure into pain, and pain into pleasure, than custom and repetition. P. 271
The more you do something, the more you become numb to it. If you do something dangerous enough times, it will not seem dangerous.
Confusing:
Thus it appears, that the principle, which opposes our passion, cannot be the same with reason, and is only called so in an improper sense. P.266
I feel like this contradicts itself. I do not see the difference between principle, passion, and reason. They all seem to be very similar.

The same good, when near, will cause a violent passion, which, when remote, produces only a calm one. P.269
I do not understand how this happens. What is an example of this?

There is another phenomenon of a like nature with the foregoing, viz. the superior effects of the same distance in futurity above that in the past. P.275
I do not get what the difference between the future and the past is. I did not understand why they had different meanings to them.