I have the option of going to Paddington and catching the fast train, or just hopping on the slower train locally. The fast train combo gets me to Reading around 10 minutes sooner, but the stopping train is a lot less bother (and doesn't involve Proper City Commuters, who will have your leg off if you delay them by a picosecond).

It's not knackering as such - a ten minute walk, a fifty minute train ride (where I'll always get a seat) and a fifteen minute cycle. It does, however, take up a very large lump of every day. Reading, emailing or dozing makes the train way better than driving, but sometimes I'd like to be doing other things with that time.