It depends if it is really a texture, then the texture has to be matched. If it's just old paintjobs stipple from the roller, then that can sometimes be pretty hard to match. If the house is old and the rooms have been painted many times, it can be difficult to get new smooth patching to look like that. If you are using a 3/8" nap roller cover and the walls were originally painted with a 3/4" nap, then this could be part of the problem. Sometimes I will spot prime the new patches with a thicker nap to try and get the new to match the old, but this doesn't always work perfectly and the only solution is to skim coat the entire room which means floating a coat of new drywall compound over the entire area and then sanding that smooth before painting.

Any paint with any sheen to it at all will magnify the imperfections in the wall. You might want to try Ben Moore Matte finish paint which is flat but very durable for wet areas.

We had a bedroom where the wall was badly damaged at one point and the repairs were less than perfect. The way I disguised it was to do a sponge paint treatment over top in a second color...same color but a shade or 2 lighter so it gave an intentional textured look to the wall...it completely masked any imperfections.

Another alternative is to wallpaper.

Thank you for your above replies! To clarify, the walls were orginally wallpapered (just one layer) from the 70's. The wallpaper was thick vinyl, had glue rolled on to the back (yes, that long ago) and was placed on the walls with no prepping such as Kilz. It is a miracle the walls are not in worse shape.

In painting the walls, it took coats and coats of Kilz and paint, as the walls were so dry they seemed to absorb anything placed on them. This is the first time the walls have been painted, but the area I am painting now is new, so to speak. I believe the slight texture came from the stipple from the roller, as it seems to match our other walls in the rest of the house. I wonder if it will help to use Kilz and try a new roller nap. At this point, I don't think I have many other options. Since we just took down wallpaper, I think I will skip that option. We are at the point of being almost finished, so I am trying to bring this to an end.

I like messing with things like this. You can give the paint some texture by using a sea foam sponge. Small is best. Dip in paint and touch on wall without moving to give it a stipple texture. Let thoroughly dry and go over again if necessary, add a final layer of paint with a heavy nap roller. Depending upon the amount of roughness, you may not have to wait for the coats to dry.

You could also leave a dish of paint out to dry overnight. This should thicken the paint. Then use a layer of this with a heavy nap roller. Whatever layers are needed to a build up.

You can build up some roller stipple texture by using a high build primer so the smooth patched areas look more like the other walls. Can't see what you're doing, but you might want to paint that whole wall to even it out. Home Depot sells Peel Stop Triple Thick which works.