Most frequently occuring problems in Oracle

What are the top ten problems most frequently occurring in the real world usage of Oracle databases?

The problems that I most frequently come across can be divided into two large categories: SPACE PROBLEMS and PERFORMANCE/MEMORY MAINTENANCE PROBLEMS.
In the space problems category, you will most likely find:

• table reached its max extents
• index reached its max extents
• cannot extend tablespace because MAXSIZE reached or no space in drive
• archiving error because ARCH process did not find space to copy the archived logs

In the performance problems category, you will most likely find:

• problem in SHARE_POOL_SIZE (increase size)
• number of processes reached its max
• locking problems
• ora-1555 snapshot too old (read consistency problems)
• The big slow performance problem

Perhaps the most popular problem is when a programmer/manager comes to you and says something like "the application runs slowly -- you have a problem in the database! This is definitely the hardest problem to solve because there is no "cook book" solution.

*taken from searchoracle.com