Modest Mouse are one of those bands that at one time meant a whole lot to me. I haven't heard their last 2 or 3 records. The last one I picked up was The Moon and Antarctica and I just kind of lost interest after that. To be fair, that record has such a strong association in my mind of a person, time, and place that it's maybe more due to that than anything that I moved on from the Mouse. After that record I actually stopped listening to them for many years and only recently did I rekindle my interest in them.
Many bands from that era were a joy to watch evolve from small club band to decent sized theater (and sometimes beyond) sized audiences. I was an avid show goer back then and have an enviable roster of bands I got to see. One of the only joys of being of a certain age! I first saw them at Bottom of the Hill and progressed with them to their multi-night stands at the Great American Music Hall. This was also the evolution of Sleater-Kinney, but i digress.
The appeal of the band is fairly clear in the same way that the Mountain Goats appeal is clear. Sad and angry songs for emotional misfits. People that have had rough lives, seen some shit, and use music as catharsis. In thinking back on Modest Mouse show going experiences I would say that it's similar to a Mountain Goats show going experience. The song Trailer Trash is a good example of the emotional side of Modest Mouse. This song always had a high level of crowd participation. A favorite of many, including me.