Google Personalised Search Tools
Google personalised search/web history is a service provided by Google intended to customise results for an individual user. In some instances this may not be desirable, and in others, you may want to see what results look like without those customisations.
Search without personalised results
Disable/enable personalised search features
The following link enables you to opt out of personalised search features: Personalised search opt out.
You can restore personalised search features using this link: Personalised search opt in
Delete/restore web history
The following link will completely delete and disable your web history with Google: Delete web history.
You can restore the web history service with the following link: Restore web history service (note: this won't restore your data)