Here are 3-no, 4--things you shouldn't do in EW
If you're new to EW, or coming from a background in FP, there are some gotchas waiting. Here are some I've found the hard way. For instance:
1. If you have a paragraph block of text, resist the temptation to use those handles to resize it. If you do that without first giving that block it's own unique ID that dimension you just specified can get written back to the style sheet and try to force other paragraph blocks using that same style to be the same size. Which will mess up a whole lot of stuff. And make you crazy.
2. If you are using tables and have inserted an image into one cell, resist the impulse to drag that picture into a different cell. Nine times out of ten, no problem. That tenth time? EW crashes. FP Cleaner (mentioned elsewhere) can help, but not always. Cut and paste instead.
3. If copying a block of text from another page, and that text has a whole bunch of links in it, don't count on EW accurately preserving all of those links, even if the checkbox to do that is checked. Verify the links! All links!! Sometimes the links you brought in point to the directory on your computer the web is stored in, not to the web itself, even after saving. The dropping of links mostly seems to happen when you bring in more than a half dozen links at once. Why? No idea.
PS, do use the Paste Text, rather than a straight paste, if bringing stuff in from a page written in FP. If you don't you'll be bringing 'bad' styling in with you. Put in plain text, then apply your chosen style.
4. Freak and feel despair when your pages, when previewed with Firefox, have overlapping blocks of text. For some reason sometimes the space between those paragraph blocks is not being observed or rendered properly. Fixes: check to make sure those blocks have the proper margin--sometimes you will find they have a specified value that isn't displayed under the styles.Set them manually. Cheap & ugly temporary fixes: go to the block that the one below is overlapping, and make it one line taller by hitting <control> enter to drive the box edge down a line, essentially inserting a blank line. On occasion you can even later delete that line and not have things go back to a web page pile-up. Or insert a break in between the two blocks. Both of these have the downside that you've given up some degree of control over placement. The first fix is best, even if you have to fool with the top/bottom margins of the blocks of text a bit to get it right.

I've done dozens of things wrong in my changeover to EW from 10 years of FP. Thought I'd toss these out to get a new topic going.

-Steve 

1. I will agree with you that users handles to resize can lead to problems but it should create a style not change the element defaults. Check and see if you have styles set to auto or manual.

2.  I tend to copy, posts then delete. Make sure you have the image selected by using the quite tag bar at the top of the document window.

3. Make sure you save your page before you copy links and images to preserve the correct path.

4. Remove the position absolute layer and associated style. Make sure under Tools, Page Editor Options, CSS Tab that size and positioning are set to create a class not inline. Then you will see it in the CSS Properties Task Pane. Aroid using Position: absolute and the overlaps should stop..

the layouts see: http://apptools.com/examples/pagelayout101.php

1. Again we get back to the, ah,  less than exhaustive documetation. Those darn handles suggest that they might just be there to be used, and there's nothing to tell you what might happen if you give in to temptation. I sinned, I paid. I also tend to work in manual when pasting in stuff from existing pages, otherwise EW starts generating styles like crazy.
2. It can be even a simple table, 1 row, 3 columns. Picture is in left column. Drag it to the middle or right column, you're playing Russian Roulette. FP never did this.
3. Saving the page is supposed to change the link from c:../../../../../../ etc etc to pagename.htm. And it does, mostly. But not always, once again this usually happens when you're bringing a big pile of stuff from a page written in FP. Maybe I'm the only one this happens to, but it does happen. To me. Often enough to have made me gun-shy. Because of the # of EW crashes I've had I save a LOT. Didn't really have FP crashes after I upgraded from the '97 version to the 2K version. (Remember Personal Web Server installation?)
4. This happens with default (non-specified positioned) and relative positioned blocks of paragraph text, new or pasted in. and I'm sure you're right that absolute positioning will cause the same problem. Write or paste in a block of text. Hit enter. Write or paste in another block of text.  Apply styling. Save. Preview in Firefox. Cross fingers. Have tried changing size/positioning to create class as suggested and will watch with interest to see if this solves problem.. FP used to do it on occasion, but not with depressing regularity.

Firefox and EW pages can have issues. The above is one. Behaviors don't always translate well. For instance an image with a hotspot. Set it up so that mouseover causes a border to appear, mouseout allowing the border to vanish. IE6 will display it--though if you preview you get a warning about active content you have to allow that you don't get checking the page once it's published. (Go figure). In Firefox it may flicker in and out if it shows at all, in Opera, no show, at least in preview. Maybe we need a Firefox/Other Browser Problems topic? Or Issues. We could call them Issues.