[guylhem]

The question is incomplete ("contributing something positive or at least not actively doing harm").

Please define "good".

To me, good is where you find something interesting and worth doing.

Financial speculation makes the market more liquid and reduce the spread. You say you find that interesting. I would then call that "good".

If it matches your definition of good, you may want to engage in that.

If it does not match your definition of good, look at international finance, then international macroeconomics - you will see many people are actively looking to find ways to mitigate the effects of speculation.

Also, there are some interesting side problems where your mathematical skills could be applied (should monetary policy be used in a discretionary way?) for similar problems (if you define a stable economy as a "good" thing)

[mseebach]

It's not hard to see where it comes from, but intelligent people should be able to see the financial sector with a bit more nuance than knee-jerk hatred. There are many good reasons not to enjoy working there, but hand-wavy self-certain assertions that everything that goes on there lands somewhere between net negative and plain evil is just disingenuous.

Go there, learn about it, make some money while you're at it. Leave if you don't like it - it's not a sect.

[jberryman]

Where do you read "knee-jerk hatred"? The poster doesn't justify his opinion of finance, but that's not really the point of his post.

[mseebach]

Sorry, in the comments to the answers.