What are some things that are easy to do and do well?

I frequently read posts saying things along the lines of:

• Carpet is easy to lay down...poorly
• Drywall is easy to do. It’s hard to do well.

Well, what are some tasks that are easy to do and do a good job- things you'd recommend doing on your own rather than hiring out?

Edit: I'm not replying to all these, but I am reading them. Thanks for all the great suggestions and discussion!