Let’s face it, sometimes, in some professions, it’s easier to just lie than it is to try and explain something. If lawyers faced even a handful of the questions web designers faced, they’d be asked to explain the law and how their clients can represent themselves all the time.
It’s frustrating, because for example, you’d never hire a painter to paint your house, then ask him to show you how to do it yourself.
That’s why web designers have to bend reality sometimes because it’s almost necessary. If you asked a web designer to make your website have fireworks go off in the background, they’re likely to lie and say, “Oh, that isn’t really possible anymore. Future browsers don’t support that.” It’s a complete lie, but a good one because for some reason, in this business, trying to explain why it’s a bad idea to have fireworks flashing all over your web pages’ background just doesn’t register with a lot of people.
The point here is simple: if you’ve hired a true professional, listen to their advice. Don’t shrug it off and claim you know better because you don’t. Why else would you have hired the professional?