I just got my oil changed, and they made me sign a waiver that they told me that my tires had uneven tread. I know nothing about cars besides how to drive them. one was a 6/32 and the other was a 5/32 if i remember correctly; thirty-something anyways. Is this a big deal? and does that mean I only have 5 or 6 % of my tread left? The previous owner told me the tires were replaced a little less than a year ago. Is it even possible? I have 80k miles on the car.

Don't worry about it. Tires typically have 11/32nd's of an inch of tread depth when new. Yours having 5 and 6 32nd's indicate they're about halfway worn.

One note however, when you look at the tire tread, it should be evenly worn across the tread face. If the tread has been worn smooth (the ol' baloney skin) on either the inside or outside of the tread face that's an issue that needs to be taken care of.

Regarding them making you sign a waiver - I'd ask why. If you're asking them to change the oil that's what they should stick to. If they find something unsafe it's their duty to point it out - not to have you sign a waiver (they're not empowered to do so anyway). I would find another place to change the oil again from here on out. I get the impression 'somebody' was trying to sell some tires?