Well, I think some triangles are evil, but many are merely misguided.
Some are simply capricious or mischievous.
For a while, I thought HST's (half-square-triangles) would ruin my life, but I'm doing a lot better with them. My biggest improvement came when I started using Triangulations - it's a CD with many, many, many sizes of HST's & QST's.
Every month, I get ten fat eighths in a Block of the Month kit. The blocks are called "Lady of the Lake" and they consist of one large HST block and nine small ones along two edges. Triangulations lets me print exactly the same size every month and my blocks have been consistently sized for almost a year.
Of course, you DO have to get that pesky 1/4" seam right, but this month I noticed very few lost or floating points on my blocks - yahoooo! What a change!
Good luck to you and have fun with it!