You asked:
Why do eyes twitch sometimes? — Vish, Chennai, India

Marshall Brain Answered:
Speaking from personal experience… I know that when I am in a public place like a grocery store or a library, and one of the twins bumps into the other twin accidentally, so then the other twin takes offense and bumps the first one back, and this bumping quickly escalates, and the next thing I know I turn around to find the twins are in a fist fight with five adults looking on… it makes my left eye twitch.

Generally speaking, people tend to get eye twitches, also known as eye spasms of Blepharospasm, because of lack of sleep or stressful situations. There are more serious reasons to get eye twitches (e.g. neurological damage), and there can be debilitating episodes, like this:

You can talk to your doctor about treatment options if eye twitches really annoy you or become dangerous. Possibilities include drugs and surgery.

More info:

See also: Blepharospasm.org and Eyelid twitch