Racker, to some pool owners the idea of spending 15 minutes a day vacuuming leaves is torturous; other folks enjoy doing it.

I personally dislike "crap myrtles" and "flaking birches" (river birch) intensely. Actually, I like river birches quite well, as long as they are not near a pool I service. Crap myrtles, I don't like anywhere.

But there are a variety of trees that are just plain bad around pools:
+ river birches (zillions of flaky seeds, that stop up skimmers and end up everywhere)
+ hickory family nut trees (bad stains from nuts)
+ crap myrtles (they are dumping SOMETHING in the pool, 360 days of 365)
+ cottonwood (who wants to swim in fuzz?)

Some people hate pines, because the needles pass the skimmer and pump strainers, and can end up clogging the pump impeller.

. . . And so on.