Revel means to take great pleasure. If you revel in something, you're not just pleased or even excited; you're overwhelmed by joy.
It used to mean riotous merry-making. Now it means to bask in the self-reflected glow of your own pleasure. You revel in your victory lap after winning the race. Your brother is constantly on your case for being clumsy, so when he knocks down a table filled with glassware, you revel in it. Think of it as a high level of pleasure.