In my work I deal with a lot of unix and unix related things. I wouldn't be doing it if I didn't like it. There are, however, 3 things I really dislike. They are mysql, linux and php.
today is about php. please take a look at the following munin graph.
what do you think that was? that huge drop in memory usage, becoming more consistent etc.. It was me downgrading php 5.2.8 to 5.2.6 with all configs being exactly the same. php 5.2.8 turned out to be a real piece of crap. I did try it on a few webservers with high load and it does NOT perform well. the number of system calls is probably 5-10 times higher, I saw spikes in loadaverage, some pages not loading up fast etc. I recommend staying on 5.2.6 for all critical applications. it is not the first time php developers released crap instead of a stable version.