I don't even see or notice any ads. on Win10, but a few small things in Win10 irritate me - ones I can think of right now are :
1.) When you want to connect to an alternative ISP, that stupid blue window with the cog in it pops up first, before it takes you to the list - what's that all about? ; some unnecessary distinguishing characteristic, to remind you you're on a 'fancy OS'?
2.) Data usage doesn't (always) reset to zero (sometimes it does ; seems the reason might be when I don't 'use the laptop it's on, for a few days?) like it always does on 7, or 8.1 from what I can remember.
Will always prefer Win7 over 10, and I find that Ubuntu MATE / Peppermint OS at the very least, on a par with Win7 (for trivial things) ; for work, Win7's the best .. won't be happy moving to Win10 when the PC 7 is on, packs up!