It is

When contracting "it is", I'm thinking of adopting "'tis" to supplement "it's." I use "it's" a lot. Maybe I should mix it up a little.

Just go with me on this:
1. It's a shame they wanted to hate a show they paid so much to see.
vs

'Tis a shame they wanted to hate a show they paid so much to see.

2. I don't know if I can handle what it is now... it's too overwhelming.

vs 

I don't know if I can handle what it is now... 'tis too overwhelming.

3. It's nice when these things work out!

vs

'Tis nice when these things work out!

(I don't like "'tis" in that one.)

4. I don't care if it's an old-fashioned idea -- it's the dream.

vs
I don't care if it's an old-fashioned idea -- 'tis the dream. 

(See what I did there? Using "'tis" to replace the first "it's" would have been a bit much. Also, I don't think that's the way "'tis" is supposed to be used... I'm not much of a grammar nazi unless in formal situations -- punctuation, yes, but not grammar -- but I think that would be wrong.)

What do you think? Does it sound pretentious? Should I give it a shot in the next few posts and see how it goes?

If "'tis" is well-received (now that I've mentioned it I can't expect it'll be unnoticed), I might try using it in my verbal communication.

Nah. That would be pretentious!