LOL

LOL as in 'Laugh out loud' is a common texting reaction. You usually see someone say 'LOL' or lol when you post something funny, as well, it means Laugh out Loud. It can also be used as an offence, for an example:
Person 1: Ugh we lost the match
Person 2: LOL noob
Person 1: Shut up!!
You may also come across 'xD', which means the same thing. The x represents the eyes in laughter, and the D represents the face. Example of it below:

Person 1: Yesterday, in the cricket match, my team was so bad. I was the only good one and because of them we lost.
Person 2: No you were bad LOL they were the ones that we good
Person 3: ;-;