Mail and HTML - my continued search for ways to handling this

I’ve been trying to get rid of HTML in Mail but it’s difficult (impossible so far). One thing that is driving my crazy is email sent by people who are “creative” when it comes to formatting their emails, for example font colors that makes the text difficult to read, background colors that make the text difficult to read, font sizes that makes the text difficult to read, etc.

How do you people handle this, is there a way to set a font size that I prefer, remove background and font color, etc?

Yes, I know that the obvious way to handle this is to switch to, for example, MailMate but I’m trying to do this in Mail.

Mozilla Thunderbird can be set to default into Plain Text.