useless trivia: What Word Means: An Enthusiastic Endorsement - Quoted Praise?

Questions

Promise of future benefits e.g. pensions or share options for those who stay with a company?

Planting of trees in urban or desert areas?

Traffic jam affecting a whole network of intersecting streets?

Anonymous letters of hostility towards the recipient?

Gesture of celebration in which two people slap each others palms with their arms outstretched over their heads?