Why is Steam so badly coded?

[w00t951]

When I try to do anything on Steam, the processor usage skyrockets and the entire program lags and/or beachballs. If I try to download something, Steam usually crashes. Does anyone have a fix for this? Thanks.

 

[Libertine Lush]

While idle, with no games running, I do see the CPU load and temp go up quite a bit sometimes. My only remedy is to restart the client.