I always read things I'm about to sign, even if it annoys the staff. It's too much of a risk to just agree and hope all will be Okay. I'll not sign stuff that has clauses about binding arbitration or mandatory data sharing with other organisations.

I was signing up for a phone and started reading the T&Cs. Two pages of super small text. The staff member was surprised and said "No one reads that, it's just standard stuff". After a few minutes he starts pressing me to sign it as their system will cancel a signup not completed within five minutes. I doubt that 5-min timeout was a deliberate attempt to coerce people to signing up without reading the terms, but it certainly shows just how little people care about that stuff if they don't account for reading time in their signup process.