if they sneak up on you ctrl-w closes the tab
and ctrl-tab changes to the next tab
you can also press control and then any number to go to that number tab
so say you have youtube open as your first tab and imgflip second
ctrl-1 gets you to yt quickly :]
If you're on Chrome, just make a tab group that isn't a suspicious name, then you can just click the group heading and the tabs inside the group are hidden