I was wondering, some of the tomatoes I have harvested this year do not look, taste, or seem like what I have labeled to come from said
plant.?? Since I do not bag my blossoms and plant my own harvested seeds from the previous year, is this what happens: unintended crosses??

@indysun , unintended crossing does occur and if what you are seeing is not what you are expecting, then it quite likely has occurred.

What to do now depends upon whether you like the fruit you are currently harvesting more than the named varieties that they came from. If you do, keep growing the plants, keeping track of how many generations you have grown them for. Tomatoes take 8 generations to be stable nominally, varies a little bit depending upon how similar parents are.

If you do not like this years fruit over the named varieties,. You may have to re-purchase seed or go back to original packet assuming you still have it.

Whwoz has summed this up very nicely and his advise is spot on. If your fruit is not what you expected from your own saved seed then it is either a cross or you may have mislabeled them. So before saying that they are a cross check to see if they may not be a mislabeled variety.