Hello everyone!

This is a phrase that's pretty new, at least to me. I don't know how it caught on but it's kind of redundant. If something is illogical, it doesn't make sense. You don't need to put the two together.

Not necessarily, An example of something that makes illogical sense:
My puzzles.

lurkermode=false :P

I used a command line switch to make that comment, so I didn't even have to change my lurkermode setting to "false". =P

Hmmm i was sure for a few moments you were quoting a vulkan saying...

Time to shut down my brain... xD

A house needs to be demolished for a new housing project to be built. The housing project will give work to hundreds of people, and offer affordable housing to hundreds more. In the house lives an old lady, that refuses to leave. Will you force the old lady out of her house and demolish it, or will you allow her to stay there, thus forfeiting the housing project?

Which is the logical choice, and is it also the choice that makes sense?

Put the old lady in a retirement home and demolish the house.
We have the same problems in some smaller villages/towns, I guess you guys in Greece too (although your climate is better :)). Houses are breaking, half of the house has no windows and is full of snow/water and then they can't demolish it because some old lady refuses to leave. Heh! If you speak Swedish, translate me Hejsan Svejsan. Worse redundancy :D
BUt please humour me, how is "Hello everyone" redundant? Do you mean that by saying Hello you automatically mean it to everyone?

He isn't talking about "Hello everyone", that was just the opening to his post. He's talking about the thread title, "Making logical sense".

Oh... oh.....

The holidays are getting the best of me already.... it seems.

From Wiktionary:

make sense (intransitive, idiomatic) To be sensible, coherent, reasonable.

logical (not comparable) In agreement with the principles of logic.

Way I see it, the two can complement each other. The sensible/reasonable doesn't always agree with logic.

When we compare prices, $2.99 registers as significantly cheaper than $3.01.

We feel more satisfied buying a pair of $40 dollar jeans if they are discounted from a fictional $60 dollars price tag during a sales period instead of buying the same pair of jeans undiscounted for $40 all year round. Attempting to establish the latter system is killing JCPenney right now.

Both examples make perfect sense because of the way our brains are wired, but it is highly illogical...

Hence my post earlier: it's easily misconstrued.
Also, speaking of redundacy: typing "Hello everyone" at the beginning of an OP in a public forum topic. =P

I'm pretty sure Penney's eased off on that, and might have killed that experiment entirely. I don't know if they have as many sales as they did before they enacted that policy, but they do have somewhat regular sale discounts once more.

It's not really redundant so much as for emphasis. But, there are other types of sense other than logical. For example common sense. A lot of what I do is anti-rational and that's a completely different sense from logic.
People who don't understand how numbers work think that $2.00 is significantly less than $3.01. However, most people fall for the deep discounts just because there's not much objective difference between something that people routinely pay $40 for and $60 for respectively in most cases. We're responding to the time limited nature of the deal without bothering to fully evaluate the choice.