NO. NEVER. EVER. But, I tend to buy more Miatas rather than sell them.
That being said, I do sometimes get tired of fixing this or that or tinkering, but I always come back around. My Miatas have always been daily drivers until I started having more than one - then I daily drive only one of them.
Don't get me wrong, I like other cars and Rovers (which I will buying another soon), but I can't find anything I MUST have. The Audi R8 is about the only car I would consider, but I am loathed to spend the money.
I have been looking around at purchasing some older sports cars that I couldn't afford when I was younger, but I would always keep at least one Miata around.