My pet hate is links in emails. I mean, how hard could it be for email clients to show the actual address it's going to, and make it so you have to copy & paste, not click. I especially hate companies like Fedex that send payment links by email, leaving me always wondering if it's spoofed, or really from them and I'll get penalised for not paying something that really is due (but no human contact number to check, of course).