Taxi drivers always expect a tip even though they are going the long way,in your mind.Getting a taxi when you're steaming must be their worse nightmare though having said that only time they make a few bob.
Mate, if I had a tip from every drunken ****wit who cant remember the name of the bar they're going to, threatens to piss themselves on the way, then makes you drive round in circles looking for a cashpoint, I'd be able to retire tomorrow. Then there's the ****s who know a quick way and won't be argued with even though you try to tell them that there's roadworks on the Embankment, who then blame you for the traffic and sit silently hating you all the way to their destination. Not to mention the tossers who book a cab to go from Putney to Kings Cross at 4.00pm on as Friday and only allow 30 mins for the journey, causing them to ask you things like "how long will it take?", and "can't we go the quick way?".
When I get into a cab that's on the meter, I tell the driver I'm going to give him, say, £5 for the trip (variable depending on the journey). The size of his tip depends on how quickly I get to my destination. Works a treat.