In instruction pipelining, there are different problems called hazards that can slow down how instructions are processed. Let’s break these down into simpler parts.

1. Structural Hazards
These happen when two or more instructions try to use the same piece of hardware at the same time.

For example, if a CPU has a narrow data path or only one memory port for getting instructions and accessing data, structural hazards can occur. When this happens, the pipeline has to pause or change how it runs the instructions. This can slow things down.

2. Data Hazards
Data hazards occur when one instruction relies on the results of another instruction that isn’t finished yet. There are a few types of data hazards:

• Read After Write (RAW): This is when an instruction tries to read a value that hasn’t been updated by an earlier instruction.
• Write After Read (WAR): This happens when one instruction wants to write a value before another instruction reads it.
• Write After Write (WAW): This takes place when two instructions try to write to the same spot. The order of these writes can change the final result.

3. Control Hazards
Control hazards are about what happens with branch instructions. When a branch instruction is taken, it’s not always clear what the next instructions will be until the branch is resolved. This uncertainty can lead the pipeline to grab the wrong instructions, which causes delays. To fix this, the system might need to pause or use prediction techniques.

It's very important to manage these hazards to make the performance of pipelined systems better. Techniques like data forwarding, branch prediction, and adding more pipeline stages help reduce these problems. They allow for smoother instruction processing and improve overall efficiency.