Lights can flicker for various reasons, ranging from minor issues to more serious electrical problems. Here are some common causes of flickering lights:

1. Loose bulb: If a light bulb is not screwed in tightly, it can cause intermittent flickering.

2. Type of bulb: Certain types of bulbs, such as fluorescent or LED bulbs, may flicker if they are used with incompatible dimmer switches.

3. Dimmer switch bulbs: Old dimmer switches designed to work with incandescent bulbs may not work well with LEDs.

4. Loose plug connection: If a plug is not making proper contact with the socket, it can cause flickering.

5. Circuit overload: If too many appliances or electronics are connected to the same circuit, it can cause flickering.

6. Loose wiring: Loose or outdated wiring can cause flickering and is a major cause of house fires.

It is important to address flickering lights promptly, as they can be a sign of a more serious electrical issue. If simple fixes like tightening bulbs or upgrading switches do not solve the problem, it is best to contact a professional electrician to diagnose and fix the issue.