I'm constantly surprised at many grads' attitude toward teaching: don't like it, don't want to do it. Our department Lead GTA (a thankless job for a miniscule pay raise) started a monthly department brown bag seminar on teaching topics, and was assessing interest. I had slept in (and we'll ignore the fact that I wasn't up early enough to attend a seminar that started at 11), but the response from others in the immediate vicinity was along the lines of "I don't want to teach ever again". I got a similar response from one TA I asked for advice on my current class; while the other was incredibly enthusiastic about it, she's also on a year of temporary leave as she considers changing careers away from semi-meaningless research. Here I'm halfway to requesting a TA every school year, and everyone else is begging their advisor to be RA-only.
I freely admit that my attitude as I gathered my belongings to head to my lab this morning was along the lines of "I don't want to do this...". However, this was no different and no stronger a reaction than my usual attitude when going to a class of my own or a meeting with my advisor. Not the best attitude to have, I admit, but far more reflective of the anxiety of putting myself on display than of what I was about to do. As soon as the family arrived or as soon as I step into my classroom, the attitude to adjusts to a more dignified version of "let's get this party started".
As for the activity itself, I certainly prefer teaching to sitting around collecting data. It's more interesting and challenging to fumble around for definitions of concepts than to count trials so I'll be ready to push the "next" button when it appears. The benefit of my research experience, at the moment, is that I'm mostly inured to the drooping eyelids and slack faces of my undergraduates during most of the class period. I know I'm not entertaining, and the subject matter can't all be thrilling. At least with a class, there are always at least a few who pay attention, and they're only going to make disparaging comments outside of class.