I hate when they won't let me use a password that's not "strong" enough. I picked my password, let me use it. I know the consequences of using an easy password.
I hate when they won't let me use a password that's too strong. Nothing makes less sense to me than rejecting a password because it contains '!' or '#'.
They already blame the bank and the internet when they have to change their password after every login because you've forced them to set it to something completely non memorable.
Having stronger passwords reduces the risks to them as well. Support costs when your account is hacked, news flow when accounts are broken into (which often don't discriminate between the app's fault and the user's). If all passwords are strong, a password dump has reduced risk.
After having two of my passwords leaked via app breakins, I now use a password manager and make sure even the most arb of sites share nothing, each password is strong, and my master password is first class. Sure there's still a risk. Much lower than before.