I'm a web developer by trade. With that being said, I browse with javascript disabled via a lovely tool for Firefox called NoScript (yes, believe it or not, people actually browse with javascript disabled! *gasp!*). It allows me to enable or disable javascript on a domain-by-domain basis. It's very handy.

However, it's very irritating to be stumbling through the web and have websites tell me that I don't have the latest version of the Flash player installed. Guess what? I do have the latest version of the Flash player installed. I'd be giving you a page impression if you weren't trying to tell me to update my Flash player. Instead, I'm gesturing back, Alt-LeftArrow'ing, or middle-clicking your tab.

Stop it.