Am I crazy?
Nope. Because as a successful freelancer you have to look at the long view. I've been doing business with this client for a while. They pay on time. They have reasonable budgets. I want them to be happy. If they are happy, they will call me again. If I'm a pain in the butt they won't.
I can hear you ask... "But what about the clients who are a pain to work with?"
You have to take a few things into consideration. How busy are you? If you're not busy, it's better to "grin and bear it" and earn the bucks.
If you are busy, then the next time you do an assignment, work out ahead of time exactly how much you will be billing if their project goes "over". Remember NO SURPRISES.
A fellow designer friend of mine said that he found that some clients are "grinders". They keep making small changes. But after a while you find that they have ground you down and eaten lots of your time... when you find your self working with a grinder, sometimes, even if you are slow, it's a good thing to charge more... even if there's a chance to lose the account.
Explain to them that it's "only fair" that you charge them more since they are demanding a lot of your time.
Bottom line: You can be working long hours and go out of business being busy with some clients. But if your client is a good client and you get caught in an assignment that runs longer then you expected.. go with the flow. I'm sure that in a years time you will do assignments for that client that take less time and so in the long view... it evens out.
Your client is happy, you're happy.